header-sensitive beginning-of-line?

[Benjamin Rutt <rutt+news@cis.ohio-state.edu>]

It might be nice if message-mode had a way to allow you to navigate
point to the beginning of the header value.  This would make it easier
to trim out values if you typed in the wrong email address, or
newsgroup, or subject line.  For example:

Subject: C-a currently moves point to beginning of line
^
^
^

Subject: WIBNI the cursor could end up after the ': '?
         ^
         ^
         ^

Maybe message-mode could have a function named message-bol which would
place point just after the ': '.  (Similar to how C-c C-a
(comint-bol-or-process-mark) operates in shell-mode.)  Maybe we could
define C-a in message-mode to run a new function `message-bol' which,
if point was in the header, would navigate to just past the ': '.  Two
consecutive invocations of `message-bol' could navigate point to the
true BOL.

Any thoughts?
-- 
Benjamin Rutt <rutt+news@cis.ohio-state.edu>