style: Fix typo in pull request template

[hyperupcall]

Before submitting a pull request, please make sure the following is done:

• Fork the repository and create your branch from master.
• If you've added code that should be tested, add tests!
• Ensure the test suite passes.
• Format your code with ShellCheck.
• Include a human-readable description of what the pull request is trying to accomplish.
• Steps for the reviewer(s) on how they can manually QA the changes.
• Have a fixes #XX reference to the issue that this pull request fixes.

ShellCheck lints code. shdoc is something that would format code, but I see that using it modifies most of the script.

Also just a heads up, I noticed that in CODE_OF_CONDUCT.md, the contact email under "## Enforcement" still shows TBD@TBD.tld.

[karbassi]

LGTM 👍🏽