patch: properly escape \ in string literals
Python 3.8 will emit a SyntaxWarning for str/bytes with invalid
escapes. This commit addresses 4 occurrences where we had a bare
\ in a str/bytes.
Differential Revision: https://phab.mercurial-scm.org/D5818
#require clang-format test-repo
$ . "$TESTDIR/helpers-testrepo.sh"
$ cd "$TESTDIR"/..
$ for f in `testrepohg files 'set:(**.c or **.cc or **.h) and not "listfile:contrib/clang-format-ignorelist"'` ; do
> clang-format --style file $f > $f.formatted
> cmp $f $f.formatted || diff -u $f $f.formatted
> rm $f.formatted
> done