Use pattern operator for all possible string kinds

[jevanlingen]

What's changed?

The pattern operator is supported for all possible string kinds.

What's your motivation?

The parser did only support the pattern operator for slashy strings (~/<pattern>/). Though by convention slashy strings are used most for the patten operator, you can use every kind of string:

The pattern operator (~) provides a simple way to create a java.util.regex.Pattern instance. While in general, you find the pattern operator with an expression in a slashy-string, it can be used with any kind of String in Groovy - docs

[MBoegers]

Just quickly scanned, I have no big parser knowledge