patch 9.1.1391: Vim does not have a vertical tabpanel

Problem:  Vim does not have a tabpanel
Solution: include the tabpanel feature
          (Naruhiko Nishino, thinca)

closes: #17263

Co-authored-by: thinca <thinca@gmail.com>
Signed-off-by: Naruhiko Nishino <naru123456789@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/feature.h b/src/feature.h
index 703a72f..56d1958 100644
--- a/src/feature.h
+++ b/src/feature.h
@@ -524,6 +524,13 @@
 #endif
 
 /*
+ * +tabpanel		Tab SideBar
+ */
+#ifdef FEAT_HUGE
+# define FEAT_TABPANEL
+#endif
+
+/*
  * +browse		":browse" command.
  *			or just the ":browse" command modifier
  */