cleanup: drop redundant character escapes from `[]` character sets Flagged by PyCharm. Most special characters lose their special meaning inside square brackets. The `-` in util.py doesn't need to be escaped because it is the last character in the set. Differential Revision: https://phab.mercurial-scm.org/D7766

cleanup: replace contiguous spaces in regex patterns with an explicit count Flagged by PyCharm, this form should be more readable. Differential Revision: https://phab.mercurial-scm.org/D7765