patch 8.2.3970: error messages are spread out

Problem:    Error messages are spread out.
Solution:   Move more errors to errors.h.
diff --git a/src/ex_eval.c b/src/ex_eval.c
index f469042..4f4a0a6 100644
--- a/src/ex_eval.c
+++ b/src/ex_eval.c
@@ -1770,7 +1770,7 @@
 	    if (end != NULL && *end != NUL
 				      && !ends_excmd2(end, skipwhite(end + 1)))
 	    {
-		semsg(_(e_trailing_arg), end);
+		semsg(_(e_trailing_characters_str), end);
 		return;
 	    }