patch 8.1.1746: ":dl" is seen as ":dlist" instead of ":delete"

Problem:    ":dl" is seen as ":dlist" instead of ":delete".
Solution:   Do not use cmdidxs2[] if the length is 1. (closes #4721)

src/version.c

@@ -777,6 +777,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1746,
 /**/
     1745,
 /**/