[clang-tidy] Add comment format configuration to `bugprone-argument-comment`

TL;DR: Add `bugprone-argument-comment.CommentTemplate: ` configuration option.

It would be nice if users could have more control over the comment format that `clang-tidy` considers to be an argument comment. Common use-cases seen in the wild include:

- `/* parameter_name */ arg`
- `arg /* parameter_name */`
- `/* parameter_name = */ arg`

Currently only (exactly) `/*paramter_name=*/` works, so the above are not checked for correctness.

Start with the clang-tidy bugprone-argument-comment check and trace how its current argument-comment format is recognized and configured. Compare the existing behavior with the three formats in the issue, then verify that a CommentTemplate regex controls which comments are checked and that the check's relevant tests cover the supported forms.

Written by the indexing model from the issue text.