fix for quoted attributes returning "§" (#26)

[brettalewis]

I noticed that when the regex for finding the strings ran, it was not actually finding the entirety of the string (it was grabbing the last character or two). I altered the regex to make the entire string within the quote be selected by making the original content variable a non-capturing group and making the repeated group the variable instead.

Doing this seems to fix all the issues where I saw the "§" value appear after tokenization. I manually tested this using any of the examples mentioned in the issue or the other PR attempting a fix:

footprint[uid="ca135f26-2b55-db63-7451-5a8effb2a19f"] > pad[uid="100a8763-0d5f-de60-23a5-00d74f3ecad7"]
[data-abcde="abcde"][data-xyz="xyz"]
a[attr="abcde"][attr="123"]

I also tried more complex examples where quotes may be escaped within the quote:
div:contains("this isn't \"correct\"")
div:contains('this isn\'t correct, "either"')

[LeaVerou]

Thanks!