When looking up a help topic, the key is now only matched against the
short names for each topic, and not the header. So
hg help 'Environment Variables'
must be replaced with
hg help env
The helptable is used for helptopics listed in the manual
page, so the order of topics should not be random.
Convert it from a dictionary into a tuple of tuples.
Also reorder helptable entries to keep previous manual
page order.
gendoc.py is a script generating a part of the manpage (the commands
help and options) from the docstring in commands.py.
It avoids duplicating the doc between the doc/ directory and the docstrings.
To generate the manpage, 'make doc' will create all the necessary intermediate
files.
