pycompat: introduce an alias for urllib.unquote
We have to use unquote_to_bytes on Python 3, so we need an abstraction
for this.
keyword: handle filectx _customcmp
Suggested by Yuya Nishihara:
https://www.mercurial-scm.org/pipermail/mercurial-devel/2016-October/089461.html
Related to
issue5364.
mail: do not print(), use ui.debug() instead
Since print() can't take a bytes output, it's pretty useless in Mercurial
on Python 3. As this is a debug message, switching to ui.debug() seems fine.