vim-patch:8.1.0753: printf format not checked for semsg() (#16378)

Problem:    printf format not checked for semsg().
Solution:   Add GNUC attribute and fix reported problems. (Dominique Pelle,
            closes vim/vim#3805)
b5443cc46d

(Most of the changes do not apply because Neovim already uses PRId64 and other spelling mistakes were already fixed.)

src/nvim/ex_docmd.c

@@ -6184,7 +6184,7 @@ static void do_ucmd(exarg_T *eap)
         }
       }
 
-      // break if there no <item> is found
+      // break if no <item> is found
       if (start == NULL || end == NULL) {
         break;
       }