A handful of help-related patches

[Chris Webb <chris@arachsys.com>]

Whilst looking at git-rebase, I noticed I have a few local git --help
related patches from a couple of years ago that I use on my own systems.

I'm not sure whether they're just personal quirks, but I thought I should
post them to the list in case they're of wider interest or might be relevant
upstream.

The first two patches allow the HTML path used by git-help --web to be set
in .gitconfig, and allow it to be a URL prefix, so you can do

  [help]
    format = html
    htmlpath = http://git-scm.com/docs

git wibble --help will then open http://git-scm.com/docs/git-wibble.html
instead of /share/doc/git/html/git-wibble.html in your browser.

The third patch adds a help format called 'usage' making git wibble --help
equivalent to git wibble -h, i.e. printing short command-line usage
information. (Generally that's what I want and I end up rather surprised
when I get an unwanted man page because my fingers are trained to type the
more universal --help rather than -h.)

This 'usage' help format is also good for making --help do something useful
other than produce an error message on our cut-down servers without man
pages, web browsers and so on.

Best wishes,

Chris.