global: make some docstrings raw strings
Python 3.8 emits a SyntaxWarning when a str/bytes contains invalid
\ escapes. Various docstrings in our code base contain invalid
\ escapes.
This commit turns those docstrings into raw strings.
Differential Revision: https://phab.mercurial-scm.org/D5816
{
"conduit_uri": "https://phab.mercurial-scm.org/api",
"repository.callsign": "HG",
"arc.land.onto.default": "@",
"base": "hg:.^"
}