[IntelliSense] [Readme] Documentation for tailwindCSS.experimental.classRegex

[ADTC]

Could we have documentation for tailwindCSS.experimental.classRegex in the Experimental section of the Readme? The acceptable values and what exactly happens with them isn't very clear, and there are only sample regexes floating online (in Stack Overflow etc.)

Thanks.

[wongjn]

At least for now, a fuller explanation can be found at #7553 (comment)

[ADTC]

Thanks! We should work on bringing this to the official Readme.

The vital point seems to be:

Both regular expressions must contain exactly one capture group.