Tidy up and fix enclosing paren detection in PSQ001.

Previously, we'd skip the first enclosing paren in statements like
"foo ((" which would cause the second matched paren to be marked
as too far away from "foo" whilst omitting the first paren.
Merge pull request #12 from smspillaz/common-universal-cmake.item_11

Tidy up and fix enclosing paren detection in PSQ001.