bash: simple reimplementation of _get_comp_words_by_ref
Add a minimal implementation of _get_comp_words_by_ref so
$ git show head:g <tab><tab>
on bash 4 can complete paths within the head commit without requiring
the bash_completion functions to be loaded. This is a follow-up to
the previous patch (bash: get --pretty=m<tab> completion to work with
bash v4).
Based on bash-completion 2.x (commit
bf763033, 2010-10-26) but tweaked
for simplicity and to allow zsh to parse the code.
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Improved-by: SZEDER Gábor <szeder@ira.uka.de>