Support prefixed / non-standard class names

[onetrev]

Currently the regex used for this extension -> const classNameRegex: RegExp = /[.]([\w-]+)/g; will only accept standard class name characters. However, you can (as of CSS 2.1) escape non-standard characters in your CSS. So hopefully support for this can be added. This is also applicable for anyone using TailwindCSS, but there are lots of other use cases for classes such as:

.md\:absolute
.sm\:w-1\/2

Of course when you are autocompleting they need to show up sanitized, with the escape character removed so like so:

.md:absolute
.sm:w-1/2

I've noticed this is supported in this extention I believe using the two functions at the bottom of this file.

[skyrpex]

Is this the regexp that parses the class names? Maybe it just needs to be less restrictive.

https://github.com/zignd/HTML-CSS-Class-Completion/blob/master/src/parse-engines/common/css-class-extractor.ts#L9

[LoranKloeze]

I have fixed this in my fork: https://github.com/LoranKloeze/HTML-CSS-Class-Completion-Reworked