patch 8.2.4012: error messages are spread out

Problem:    Error messages are spread out.
Solution:   Move the last error messages to errors.h.
diff --git a/src/regexp.c b/src/regexp.c
index 115231e..c9e781b 100644
--- a/src/regexp.c
+++ b/src/regexp.c
@@ -1495,7 +1495,7 @@
 {
     if (re_multi_type(peekchr()) == MULTI_MULT)
     {
-       semsg(_("E888: (NFA regexp) cannot repeat %s"), what);
+       semsg(_(e_nfa_regexp_cannot_repeat_str), what);
        rc_did_emsg = TRUE;
        return FAIL;
     }