contrib/win32: update build instructions after
cbe400a8e217
doc: make links for hg role
The system has a bit of smartness:
:hg:`update` -> links to hg.1.html#update
:hg:`help diffs` -> links to hg.1.html#diffs
doc: add generic frontend to rst2man and rst2html
This will allow us to easily register new roles and directives.