Fix rich_text highlighting bug with .cr file with a quotation mark

Summary

The syntax highlighting logic for Crystal (.cr) files incorrectly parses apostrophes/single quotes within comments, causing incorrect diff rendering in the merge request Changes tab. While the raw diff is correct, the syntax-highlighted version displays changes in the wrong locations.

Reported in https://gitlab.com/gitlab-com/request-for-help/-/issues/3780

Steps to reproduce

Any project on any version of GitLab;

1. Create a .cr file

test {
	hello: hi

	// asdf
	// my comment has an apostrophe 'this is all after`
	// new comment 'string'

	howareyou: good

}

1. I remove the first ' on line 5.
2. Commit to new branch and create the resulting MR
3. Check the changes tab of the MR.

Current behaviour

It would look something like this.

It seems that the rich_text highlighting logic has a bug in it as the raw text is fine.

text:

-\t// my comment has an apostrophe 'this is all after`

rich_text:

<span class=\"line\" data-lang=\"crystal\">\t<span class=\"sr\">//</span> <span class=\"n\">my</span> <span class=\"n\">comment</span> <span class=\"n\">has</span> <span class=\"n\">an</span> <span class=\"n\">apostrophe</span> <span class=\"s1\"><span class=\"idiff left right deletion\">'</span> '</span><span class=\"n\">string</span><span class=\"err\">'</span></span>