[CI] Attempts to avoid break when diff consists of one whitespace only

[CarlosNihelton]

Sometimes we fail to follow the formatting convention due to whitespaces and new lines only. In such cases CI fails to generate GitHub PR comments with the following validation error message:

{"message":"Unprocessable Entity","errors":["Pull request review thread start line must precede the end line."],"documentation_url":"https://docs.github.com/rest/reference/pulls#create-a-review-for-a-pull-request"}
Posting review comments failed with error code: 422

It seems that the start_line and line fields of a comment object must not be the same otherwise, the invariant start line must precede the end line will not hold.

            review_comments.append(
                {
                    "path": file_path,
                    "start_line": start_line,
                    "line": line_number,
                    "side": "RIGHT",
                    "body": review_comment_body,
                }
            )

This is somewhat an educated guess, because the comment object documentation is not very clear on that.

This PR aims to make sure that invariant holds by not including the start_line field when it's equal to line and further manipulation of the diff hunk target line contents to ensure we always ends with a new line if not empty.

Only commit e36ea7f is relevant code wise.

In order to demonstrate that this is behaving as expected, commits 8552fcc and 8c47a0c were created simulating the typical formatting errors that caused crashes before. The results are manifested in the github-actions-bot comments that can be seen below. The last commit just reverts those two.

[github-actions]

⚠️ Please check out carefully the isses found by clang-tidy in the new code ⚠️
⚠️ clang-format found formatting issues in the code submitted.:warning:
Make sure to run clang-format and update this pull request.
(1/1)

[github-actions]

⚠️ Please check out carefully the isses found by clang-tidy in the new code ⚠️
⚠️ clang-format found formatting issues in the code submitted.:warning:
Make sure to run clang-format and update this pull request.
(1/1)

[github-actions]

⚠️ Please check out carefully the isses found by clang-tidy in the new code ⚠️
⚠️ clang-format found formatting issues in the code submitted.:warning:
Make sure to run clang-format and update this pull request.
(1/1)

[github-actions]

Clang-format suggestion below:

Suggested change

[CarlosNihelton]

We had previous crashes due to code changes like that.

[github-actions]

Clang-format suggestion below:

Suggested change

	return false;
	return false;

[github-actions]

⚠️ Please check out carefully the isses found by clang-tidy in the new code ⚠️
⚠️ clang-format found formatting issues in the code submitted.:warning:
Make sure to run clang-format and update this pull request.
(1/1)

[github-actions]

Clang-format suggestion below:

Suggested change

	{ }
	{
	}

[CarlosNihelton]

This is exactly equal to the source change that caused the last crash.

[EduardGomezEscandell]

Great!

btw is this code unique to Ubuntu WSL? If so, no further comments. Otherwise, we should also patch upstream.

[CarlosNihelton]

Great!

btw is this code unique to Ubuntu WSL? If so, no further comments. Otherwise, we should also patch upstream.

That's unique to Ubuntu WSL. I think this piece that generates comments from a diff has a very interesting potential, but for now it's only used here.