filelog: stop proxying deltaparent() (API)
deltaparent() obtains the revision number of the base revision a
delta in storage is stored against. It is highly revlog-centric and
may not apply to other storage backends. As a result, it doesn't
belong on the generic file storage interface.
This method/proxy is no longer used in core. The last consumer was
probably changegroup code and went away with the transition to
emitrevisions().
Differential Revision: https://phab.mercurial-scm.org/D4751
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.