templatekw: move getrenamedfn() to scmutil (API)
The function is already used by `hg log` (for following renames, not
for templates), so it seems it does not belong in templatekw.
Differential Revision: https://phab.mercurial-scm.org/D6021
Mercurial's documentation is kept in reStructuredText format, which is
a simple plain text format that's easy to read and edit:
http://docutils.sourceforge.net/rst.html
It's also convertible to a variety of other formats including standard
UNIX man page format and HTML. You'll need to install Docutils:
http://docutils.sourceforge.net/
Use the Makefile in this directory to generate the man and HTML pages.