patch 8.0.0081

Problem:    Inconsistent function names.
Solution:   Rename do_cscope to ex_cscope.  Clean up comments.

src/version.c

@@ -764,6 +764,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    81,
 /**/
     80,
 /**/