SE-0357: Regex String Processing Algorithms

(Continuing a discussion from the pitch thread about a method on String to find if it’s matched completely by a Regex. Summary: There are corresponding methods for firstMatch and prefixMatch, but not wholeMatch.)

Inspired by this PR to resolve overload issues because of String’s conformance to RegexComponent:

What about equalElements(pattern: some RegexComponent) -> Bool? If other methods that also have string overloads were named similarly, that could tie in quite nicely.