patch 8.2.4005: error messages are spread out

Problem:    Error messages are spread out.
Solution:   Move more error messages to errors.h.
diff --git a/src/regexp.c b/src/regexp.c
index a30ff8b..40b21d3 100644
--- a/src/regexp.c
+++ b/src/regexp.c
@@ -552,7 +552,7 @@
 
     if (*p != delim)
     {
-	semsg(_("E654: missing delimiter after search pattern: %s"), startp);
+	semsg(_(e_missing_delimiter_after_search_pattern_str), startp);
 	return NULL;
     }
     return p;