sequencer.c: move static function to avoid forward decl

Move the reflog_message() function added in
96e832a5fd (sequencer (rebase -i): refactor setting the reflog
message, 2017-01-02), it gained another user in
9055e401dd (sequencer: introduce new commands to reset the revision,
2018-04-25). Let's move it around and remove the forward declaration
added in the latter commit.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

sequencer.c

@@ -3599,7 +3599,25 @@ static int do_label(struct repository *r, const char *name, int len)
 }
 
 static const char *reflog_message(struct replay_opts *opts,
-	const char *sub_action, const char *fmt, ...);
+	const char *sub_action, const char *fmt, ...)
+{
+	va_list ap;
+	static struct strbuf buf = STRBUF_INIT;
+	char *reflog_action = getenv(GIT_REFLOG_ACTION);
+
+	va_start(ap, fmt);
+	strbuf_reset(&buf);
+	strbuf_addstr(&buf, reflog_action ? reflog_action : action_name(opts));
+	if (sub_action)
+		strbuf_addf(&buf, " (%s)", sub_action);
+	if (fmt) {
+		strbuf_addstr(&buf, ": ");
+		strbuf_vaddf(&buf, fmt, ap);
+	}
+	va_end(ap);
+
+	return buf.buf;
+}
 
 static int do_reset(struct repository *r,
 		    const char *name, int len,
@@ -4178,27 +4196,6 @@ int apply_autostash_oid(const char *stash_oid)
 	return apply_save_autostash_oid(stash_oid, 1);
 }
 
-static const char *reflog_message(struct replay_opts *opts,
-	const char *sub_action, const char *fmt, ...)
-{
-	va_list ap;
-	static struct strbuf buf = STRBUF_INIT;
-	char *reflog_action = getenv(GIT_REFLOG_ACTION);
-
-	va_start(ap, fmt);
-	strbuf_reset(&buf);
-	strbuf_addstr(&buf, reflog_action ? reflog_action : action_name(opts));
-	if (sub_action)
-		strbuf_addf(&buf, " (%s)", sub_action);
-	if (fmt) {
-		strbuf_addstr(&buf, ": ");
-		strbuf_vaddf(&buf, fmt, ap);
-	}
-	va_end(ap);
-
-	return buf.buf;
-}
-
 static int run_git_checkout(struct repository *r, struct replay_opts *opts,
 			    const char *commit, const char *action)
 {