bash completion: Add completion for 'git grep'

Add completions for all long options specified in the docs

    --cached
    --text --ignore-case --word-regexp --invert-match
    --full-name
    --extended-regexp --basic-regexp --fixed-strings
    --files-with-matches --name-only
    --files-without-match
    --count
    --and --or --not --all-match
Signed-off-by: NLee Marlow <lee.marlow@gmail.com>
Acked-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

contrib/completion/git-completion.bash

@@ -791,6 +791,29 @@ _git_gc ()
 	COMPREPLY=()
 }
 
+_git_grep ()
+{
+	__git_has_doubledash && return
+
+	local cur="${COMP_WORDS[COMP_CWORD]}"
+	case "$cur" in
+	--*)
+		__gitcomp "
+			--cached
+			--text --ignore-case --word-regexp --invert-match
+			--full-name
+			--extended-regexp --basic-regexp --fixed-strings
+			--files-with-matches --name-only
+			--files-without-match
+			--count
+			--and --or --not --all-match
+			"
+		return
+		;;
+	esac
+	COMPREPLY=()
+}
+
 _git_help ()
 {
 	local cur="${COMP_WORDS[COMP_CWORD]}"
@@ -1482,6 +1505,7 @@ _git ()
 	fetch)       _git_fetch ;;
 	format-patch) _git_format_patch ;;
 	gc)          _git_gc ;;
+	grep)        _git_grep ;;
 	help)        _git_help ;;
 	log)         _git_log ;;
 	ls-remote)   _git_ls_remote ;;