patch 8.2.4628: not enough testing for 2/3 letter substitute commands

Problem:    Not enough testing for 2/3 letter substitute commands.
Solution:   Add more tests. (Yegappan Lakshmanan, closes #10019)
diff --git a/src/version.c b/src/version.c
index e292626..60b4c1d 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4628,
+/**/
     4627,
 /**/
     4626,