Improve PR/issues templates (#453)

* docs: Refactor `.github/ISSUE_TEMPLATE/*`

* Use <!--HTML comments--> more often & Tweak details

* docs: Add `PULL_REQUEST_TEMPLATE.md`

* chore: Temporarily fix `CONTRIBUTING.md` broken link

This patch,
just required if PR <#453>
is merged before PR <#452>,
can be reverted anytime soon.

.github/ISSUE_TEMPLATE/bug_report.md

@@ -1,42 +1,49 @@
 ---
 name: Bug report
-about: Create a report to help us improve
+about: Report a bug with this project
 title: 'Bug:'
 labels: bug
 assignees: ''
 
 ---
 
-> Related issue(s) or PR(s): 
-> Related project scope(s) (ex: client, CSS, grading, etc...) : 
-> Related user(s): 
+<!-- Some optional but useful fields -->
+
+**Related issue(s) or PR(s):**
+- #…
+
+**Related project scope(s):** …
+(e.g. UI, grading, learn-ocaml-client, Teacher-dashboard, partition-view, …)
+
+**Related user(s):**
+- @…
 
 ## Bug description
 
-A clear and concise description of what the bug is.
+<!-- A clear and concise description of what the bug is -->
 
-### To Reproduce
+### To reproduce
 
 Steps to reproduce the behavior:
 
-1. Go to '...'
-2. Click on '....'
-3. Scroll down to '....'
-4. See error
+1. Open …
+1. Click on …
+1. Then …
 
 ### Expected behavior
 
-A clear and concise description of what you expected to happen.
+<!-- A clear and concise description of what you expected to happen -->
+
+### Optional screenshots
 
-### Screenshots
+<!-- If applicable, add screenshots to document your problem -->
 
-If applicable, add screenshots to document your problem.
 ## Current configuration
 
- - OS: [e.g. iOS]
- - Browser [e.g. chrome, safari]
- - Version [e.g. 22]
+* OS name (and version): 
+* Browser name (and version): 
+* `learn-ocaml --version`: 
 
 ## Additional context
 
-Add any other context about the problem here.
+<!-- Add any other useful details about the problem here -->

.github/ISSUE_TEMPLATE/feature_request.md

@@ -1,28 +1,37 @@
 ---
 name: Feature request
 about: Suggest an idea for this project
-title: 'Feat:'
+title: 'Feature:'
 labels: feature
 assignees: ''
 
 ---
 
-> Related issue(s) or PR(s): 
-> Related project scope(s) (ex: client, CSS, grading, etc...) : 
-> Related user(s): 
+<!-- Some optional but useful fields -->
+
+**Related issue(s) or PR(s):**
+- #…
+
+**Related project scope(s):** …
+(e.g. UI, grading, learn-ocaml-client, Teacher-dashboard, partition-view, …)
+
+**Related user(s):**
+- @…
 
 ## The problem
 
-A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]
+<!-- A clear and concise description of what the problem is -->
+
+<!-- e.g. I'm always frustrated when … -->
 
 ### Wanted solution
 
-A clear and concise description of what you want to happen.
+<!-- A clear and concise description of what you want to happen -->
 
 ### Considered alternatives
 
-A clear and concise description of any alternative solutions or features you've considered.
+<!-- A clear and concise description of any alternative solutions or features you considered -->
 
 ## Additional context
 
-Add any other context or screenshots about the feature request here.
+<!-- Add any other useful details or screenshots about the feature request here -->

.github/ISSUE_TEMPLATE/question.md

@@ -7,24 +7,31 @@ assignees: ''
 
 ---
 
-> Related issue(s) or PR(s): 
-> Related project scope(s) (ex: client, CSS, grading, etc...) : 
-> Related user(s): 
+<!-- Some optional but useful fields -->
+
+**Related issue(s) or PR(s):**
+- #…
+
+**Related project scope(s):** …
+(e.g. UI, grading, learn-ocaml-client, Teacher-dashboard, partition-view, …)
+
+**Related user(s):**
+- @…
 
 ## The question
 
-A clear and concise description of what you want to know.
+<!-- A clear and concise description of what you want to know -->
 
 ### What has already been tested
 
-A clear and concise description of what you have already tried.
+<!-- A clear and concise description of what you have already tried -->
 
 ## Current configuration
 
- - OS: [e.g. iOS]
- - Browser [e.g. chrome, safari]
- - Version [e.g. 22]
+* OS name (and version): 
+* Browser name (and version): 
+* `learn-ocaml --version`: 
 
 ## Additional context
 
-Add any other context or screenshots about the inquiry.
+<!-- Add any other useful details or screenshots about the inquiry here -->

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,30 @@
+* **Kind:** bugfix / enhancement / feature
+
+<!-- For a bug fix, make sure the bug was already reported in an issue. -->
+
+* Close #…
+
+### Description
+
+<!-- Please recap the motivation and/or implementation choices for this change. -->
+
+### Checklist
+
+<!-- You can remove all the check-boxes that are not applicable. -->
+
+* [ ] Read the [CONTRIBUTING.md](https://github.com/pfitaxel/learn-ocaml/blob/add-contributing.md/CONTRIBUTING.md) guide and:
+  * [ ] Use [Atomic Commits](https://github.com/pfitaxel/learn-ocaml/blob/add-contributing.md/CONTRIBUTING.md#atomic-commits) so each commit gathers a single logical change
+  * [ ] Use [Conventional Commits](https://github.com/pfitaxel/learn-ocaml/blob/add-contributing.md/CONTRIBUTING.md#conventional-commits) regarding commit messages (needed by our release toolchain)
+* [ ] Add/update [tests](https://github.com/ocaml-sf/learn-ocaml/tree/master/tests#readme)
+  <!-- if the change impacts the grading feature. -->
+* [ ] Add/update [documentation](https://github.com/ocaml-sf/learn-ocaml/tree/master/docs)
+  <!-- if there are some user-facing changes. -->
+* [ ] …
+  <!-- you can add more items to summarize what remains to do. -->
+
+<!-- You can leave this note below as a reminder for maintainers: -->
+### Note to maintainers
+
+* Read [this wiki page](https://github.com/ocaml-sf/learn-ocaml/wiki/Checklist-for-testing-and-merging-a-PR)
+* Make sure the PR has a milestone
+* Assign yourself before merging