Set `is_bash` for `sh.vim`.
Set `is_bash` for `sh.vim`.

Even when writing old-timey Bourne shell to satisfy FreeBSD, there are
constructs that `is_bash` permits that `is_sh` highlights in erroneous
red, so I'm going to default to `is_bash` even though I'm not often
writing actual bash code.

bigeasy/dotfiles,jgpelletier/dotfiles,bigeasy/dotfiles,bigeasy/dotfiles,jgpelletier/dotfiles