Fix `string-quote` false positives if preceded/followed by a comment

[Mouvedia]

stylelint/stylelint#4298 stylelint/stylelint#6314

demo demo

[firefoxic]

@Mouvedia Hi! Thanks for the issue.

I have investigated both cases and came to the following conclusions:

• Both are not features of this specific config and/or its settings combination, meaning the problem lies in the rule itself. Therefore, this issue should be transferred to the plugin's repository.
• Both pertain to different syntaxes and do not recur if the syntax is switched from Less to Scss and vice versa.
• Both not only manifest differently, but also have different causes:
  1. In the first case (new demo), the single-line comment is not recognized by the parser as a comment, but instead, each of the slashes and what follows them is broken into separate nodes. The cause might even be in the postcss-less parser, because in the same code for postcss-scss (demo), comments are parsed correctly (but the error from the second case appears in the latter example).
  2. In the second case (new demo), there is only incorrect error location reporting, but no false-negative triggering on the comment.

Please open separate issues in the plugin's repository with their new demos:

1. Incorrect parsing of Less comments.
2. Incorrect error location due to Scss comments.

[Mouvedia]

As a contributor you should be able to transfer issues.