extdiff: escape path for docstring (issue5301) The existing code (a) assumed path would be specified in encoding.encoding and (b) assumed unicode() objects wouldn't cause other parts of Mercurial to blow up. Both are dangerous assumptions. Since we don't know the encoding of path and can't pass non-ASCII through docstrings, just escape the path and drop the early _(). Will have to suffice until we can teach docstrings to handle UTF-8b escaping. This has the side-effect that the line containing the path is now variable by the time it reaches _() and thus can't be translated.