stringutil: update list of re-special characters to include &~
I missed this because I was looking at the change that refactored
re.escape, and these characters were added in
https://github.com/python/cpython/commit/05cb728d68a278d11466f9a6c8258d914135c96c.
Differential Revision: https://phab.mercurial-scm.org/D3850
BasedOnStyle: LLVM
IndentWidth: 8
UseTab: ForIndentation
BreakBeforeBraces: Linux
AllowShortIfStatementsOnASingleLine: false
IndentCaseLabels: false
AllowShortBlocksOnASingleLine: false
AllowShortFunctionsOnASingleLine: false
IncludeCategories:
- Regex: '^<'
Priority: 1
- Regex: '^"'
Priority: 2