patch 8.2.3961: error messages are spread out

Problem:    Error messages are spread out.
Solution:   Move more errors to errors.h.
diff --git a/src/highlight.c b/src/highlight.c
index 9502428..c4f5c66 100644
--- a/src/highlight.c
+++ b/src/highlight.c
@@ -1579,7 +1579,7 @@
 		linep = vim_strchr(linep, '\'');
 		if (linep == NULL)
 		{
-		    semsg(_(e_invarg2), key_start);
+		    semsg(_(e_invalid_argument_str), key_start);
 		    error = TRUE;
 		    break;
 		}