bug#52319: imenu not detecting every bash function

["Daniel Martín via Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

fatiparty--- via "Bug reports for GNU Emacs, the Swiss army knife of
text editors" <bug-gnu-emacs@gnu.org> writes:

> I am loading the attached bash file but imenu is not showing all the
> declared bash functions in the file, it only shows PF(), PFB(), PF2(),
> and pfm.  This has also the consequence of not displaying all
> functions in speedbar.
>
> File is attached.
>
> Fati

The problem lies in that some of the functions have a hyphen in their
name (for example "linge-newline ()").  Something like "linge_newline
()" should be detected correctly.  If I'm not mistaken, POSIX requires
that shell function names only contain alphanumeric characters or an
underscore; support for hyphens could be a Bash extension.

One way to fix the issue could be to extend the
sh-imenu-generic-expression alist in sh-script.el with a specific regexp
for bash that accounts for hyphens (and any other character that Bash
may support in function names).