Syntax of "-" in shell-mode

[Dima Kogan]

Hi. What do people think about giving "-" a syntax of "word" in
shell-mode? The rationale is that in this mode one is generally editing
shell commands where "-" precedes commandline options, and strings such
as "--help" generally represent a single semantic token.

More specifically if I have something like "xxx --yyy" with the point in
the whitespace, and I invoke (transpose-words) I want the result to be
"--yyy xxx" and not "yyy --xxx". The latter means something very
different in a shell command.

dima