patch 8.2.4010: error messages are spread out

Problem:    Error messages are spread out.
Solution:   Move more error messages to errors.h.
diff --git a/src/highlight.c b/src/highlight.c
index 484634b..fa32981 100644
--- a/src/highlight.c
+++ b/src/highlight.c
@@ -3466,7 +3466,7 @@
 
     if (highlight_ga.ga_len >= MAX_HL_ID)
     {
-	emsg(_("E849: Too many highlight and syntax groups"));
+	emsg(_(e_too_many_highlight_and_syntax_groups));
 	vim_free(name);
 	return 0;
     }