Tags: patch

Find attached a “worse is better” approach for pcomplete, where we parse
help messages to generate a list of completions.

This is still a sketch.  I've added pcomplete functions for a random
selection of commands to see if this works reasonably, and I think it
probably does.  But in any case I don't think it would make sense to try
and add completions as detailed as the ones bash provides; there is an
awful lot of logic in the files under /usr/share/bash-completion and I
don't think anyone would want to redo that work.

Some further comments:

1. I'm a bit unsure whether `pcomplete-parse-help' should return a plain
   list of completions or a completion table.  The advantage of the
   former (which is the current approach) is that it's easier to
   manipulate the result of the parsing (cf. the need for that in the
   git case).  The advantage of returning a completion table is a better
   treatment of annotations.

2. I would rather not create a new pcmpl-git.el file (doing so for each
   new command doesn't seem very scalable), but I wouldn't know where
   else to put that stuff.