gopls/internal: add code action "extract declarations to new file"

[golopot]

This code action moves selected code sections to a newly created file within the same package. The created filename is chosen as the first {function, type, const, var} name encountered. In addition, import declarations are added or removed as needed.

Fixes golang/go#65707

[gopherbot]

This PR (HEAD: 8c85d43) has been imported to Gerrit for code review.

Please visit Gerrit at https://go-review.googlesource.com/c/tools/+/565895.

Important tips:

• Don't comment on this PR. All discussion takes place in Gerrit.
• You need a Gmail or other Google account to log in to Gerrit.
• To change your code in response to feedback:
  • Push a new commit to the branch used by your GitHub PR.
  • A new "patch set" will then appear in Gerrit.
  • Respond to each comment by marking as Done in Gerrit if implemented as suggested. You can alternatively write a reply.
  • Critical: you must click the blue Reply button near the top to publish your Gerrit responses.
  • Multiple commits in the PR will be squashed by GerritBot.
• The title and description of the GitHub PR are used to construct the final commit message.
  • Edit these as needed via the GitHub web interface (not via Gerrit or git).
  • You should word wrap the PR description at ~76 characters unless you need longer lines (e.g., for tables or URLs).
• See the Sending a change via GitHub and Reviews sections of the Contribution Guide as well as the FAQ for details.

[gopherbot]

Message from Gopher Robot:

Patch Set 1:

(1 comment)

---

Please don’t reply on this GitHub thread. Visit golang.org/cl/565895.
After addressing review feedback, remember to publish your drafts!

[gopherbot]

Message from tricium-prod@appspot.gserviceaccount.com:

Patch Set 1:

(5 comments)

---

Please don’t reply on this GitHub thread. Visit golang.org/cl/565895.
After addressing review feedback, remember to publish your drafts!

[gopherbot]

This PR (HEAD: 46ec4ff) has been imported to Gerrit for code review.

Please visit Gerrit at https://go-review.googlesource.com/c/tools/+/565895.

Important tips:

• Don't comment on this PR. All discussion takes place in Gerrit.
• You need a Gmail or other Google account to log in to Gerrit.
• To change your code in response to feedback:
  • Push a new commit to the branch used by your GitHub PR.
  • A new "patch set" will then appear in Gerrit.
  • Respond to each comment by marking as Done in Gerrit if implemented as suggested. You can alternatively write a reply.
  • Critical: you must click the blue Reply button near the top to publish your Gerrit responses.
  • Multiple commits in the PR will be squashed by GerritBot.
• The title and description of the GitHub PR are used to construct the final commit message.
  • Edit these as needed via the GitHub web interface (not via Gerrit or git).
  • You should word wrap the PR description at ~76 characters unless you need longer lines (e.g., for tables or URLs).
• See the Sending a change via GitHub and Reviews sections of the Contribution Guide as well as the FAQ for details.

[gopherbot]

Message from tricium-prod@appspot.gserviceaccount.com:

Patch Set 2:

(1 comment)

---

Please don’t reply on this GitHub thread. Visit golang.org/cl/565895.
After addressing review feedback, remember to publish your drafts!

[gopherbot]

Message from Chiawen Chen:

Patch Set 2:

(1 comment)

---

Please don’t reply on this GitHub thread. Visit golang.org/cl/565895.
After addressing review feedback, remember to publish your drafts!

[gopherbot]

Message from Chiawen Chen:

Patch Set 2:

(1 comment)

---

Please don’t reply on this GitHub thread. Visit golang.org/cl/565895.
After addressing review feedback, remember to publish your drafts!

[gopherbot]

Message from Chiawen Chen:

Patch Set 2:

(3 comments)

---

Please don’t reply on this GitHub thread. Visit golang.org/cl/565895.
After addressing review feedback, remember to publish your drafts!

[gopherbot]

Message from Chiawen Chen:

Patch Set 2:

(1 comment)

---

Please don’t reply on this GitHub thread. Visit golang.org/cl/565895.
After addressing review feedback, remember to publish your drafts!

[gopherbot]

Message from Alan Donovan:

Patch Set 2:

(13 comments)

---

Please don’t reply on this GitHub thread. Visit golang.org/cl/565895.
After addressing review feedback, remember to publish your drafts!

[gopherbot]

This PR (HEAD: da8e51f) has been imported to Gerrit for code review.

Please visit Gerrit at https://go-review.googlesource.com/c/tools/+/565895.

Important tips:

• Don't comment on this PR. All discussion takes place in Gerrit.
• You need a Gmail or other Google account to log in to Gerrit.
• To change your code in response to feedback:
  • Push a new commit to the branch used by your GitHub PR.
  • A new "patch set" will then appear in Gerrit.
  • Respond to each comment by marking as Done in Gerrit if implemented as suggested. You can alternatively write a reply.
  • Critical: you must click the blue Reply button near the top to publish your Gerrit responses.
  • Multiple commits in the PR will be squashed by GerritBot.
• The title and description of the GitHub PR are used to construct the final commit message.
  • Edit these as needed via the GitHub web interface (not via Gerrit or git).
  • You should word wrap the PR description at ~76 characters unless you need longer lines (e.g., for tables or URLs).
• See the Sending a change via GitHub and Reviews sections of the Contribution Guide as well as the FAQ for details.

[gopherbot]

Message from Chiawen Chen:

Patch Set 2:

(16 comments)

---

Please don’t reply on this GitHub thread. Visit golang.org/cl/565895.
After addressing review feedback, remember to publish your drafts!

[gopherbot]

Message from Alan Donovan:

Patch Set 4:

(39 comments)

---

Please don’t reply on this GitHub thread. Visit golang.org/cl/565895.
After addressing review feedback, remember to publish your drafts!

[gopherbot]

This PR (HEAD: fa8abe3) has been imported to Gerrit for code review.

Please visit Gerrit at https://go-review.googlesource.com/c/tools/+/565895.

Important tips:

• Don't comment on this PR. All discussion takes place in Gerrit.
• You need a Gmail or other Google account to log in to Gerrit.
• To change your code in response to feedback:
  • Push a new commit to the branch used by your GitHub PR.
  • A new "patch set" will then appear in Gerrit.
  • Respond to each comment by marking as Done in Gerrit if implemented as suggested. You can alternatively write a reply.
  • Critical: you must click the blue Reply button near the top to publish your Gerrit responses.
  • Multiple commits in the PR will be squashed by GerritBot.
• The title and description of the GitHub PR are used to construct the final commit message.
  • Edit these as needed via the GitHub web interface (not via Gerrit or git).
  • You should word wrap the PR description at ~76 characters unless you need longer lines (e.g., for tables or URLs).
• See the Sending a change via GitHub and Reviews sections of the Contribution Guide as well as the FAQ for details.

[gopherbot]

Message from Chiawen Chen:

Patch Set 4:

(34 comments)

---

Please don’t reply on this GitHub thread. Visit golang.org/cl/565895.
After addressing review feedback, remember to publish your drafts!

[gopherbot]

This PR (HEAD: 549739f) has been imported to Gerrit for code review.

Please visit Gerrit at https://go-review.googlesource.com/c/tools/+/565895.

Important tips:

• Don't comment on this PR. All discussion takes place in Gerrit.
• You need a Gmail or other Google account to log in to Gerrit.
• To change your code in response to feedback:
  • Push a new commit to the branch used by your GitHub PR.
  • A new "patch set" will then appear in Gerrit.
  • Respond to each comment by marking as Done in Gerrit if implemented as suggested. You can alternatively write a reply.
  • Critical: you must click the blue Reply button near the top to publish your Gerrit responses.
  • Multiple commits in the PR will be squashed by GerritBot.
• The title and description of the GitHub PR are used to construct the final commit message.
  • Edit these as needed via the GitHub web interface (not via Gerrit or git).
  • You should word wrap the PR description at ~76 characters unless you need longer lines (e.g., for tables or URLs).
• See the Sending a change via GitHub and Reviews sections of the Contribution Guide as well as the FAQ for details.

[gopherbot]

Message from Chiawen Chen:

Patch Set 5:

(2 comments)

---

Please don’t reply on this GitHub thread. Visit golang.org/cl/565895.
After addressing review feedback, remember to publish your drafts!

[gopherbot]

Message from Alan Donovan:

Patch Set 6:

(37 comments)

---

Please don’t reply on this GitHub thread. Visit golang.org/cl/565895.
After addressing review feedback, remember to publish your drafts!

[gopherbot]

Message from Alan Donovan:

Patch Set 6:

(1 comment)

---

Please don’t reply on this GitHub thread. Visit golang.org/cl/565895.
After addressing review feedback, remember to publish your drafts!