[PATCH] contrib/completion: complete options that take refs for format-patch

The completion for format-patch currently suggests --base=, --interdiff=
and --range-diff= as options. However, with these `=` forms of the
options, there is no space and we'd enter the `--*` case which means we
don't call the __git_complete_revlist() at the end.

Teach _git_format_patch() to complete refs in the case of --base=,
--interdiff= and --range-diff=.

Signed-off-by: Denton Liu <redacted>
---
 contrib/completion/git-completion.bash | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index 9147fba3d5..8be4a0316e 100644
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash

@@ -1784,6 +1784,10 @@ _git_format_patch ()
 			" "" "${cur##--thread=}"
 		return
 		;;
+	--base=*|--interdiff=*|--range-diff=*)
+		__git_complete_refs --cur="${cur#--*=}"
+		return
+		;;
 	--*)
 		__gitcomp_builtin format-patch "$__git_format_patch_extra_options"
 		return

-- 
2.28.0.618.gf4bc123cb7