Merge branch 'dm/submodule-update-i-shorthand'

The '-i' shorthand for the '--init' option, which was accepted by the
'git submodule update' command until it was broken in a modernization
of the option-parsing code, has been restored.

* dm/submodule-update-i-shorthand:
  submodule--helper: accept '-i' shorthand for update --init

builtin/submodule--helper.c

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 510f193..2b3c976 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -2990,7 +2990,7 @@ static int module_update(int argc, const char **argv, const char *prefix,
 	struct option module_update_options[] = {
 		OPT__SUPER_PREFIX(&opt.super_prefix),
 		OPT__FORCE(&opt.force, N_("force checkout updates"), 0),
-		OPT_BOOL(0, "init", &opt.init,
+		OPT_BOOL('i', "init", &opt.init,
 			 N_("initialize uninitialized submodules before update")),
 		OPT_BOOL(0, "remote", &opt.remote,
 			 N_("use SHA-1 of submodule's remote tracking branch")),