patch 8.2.3957: error messages are spread out

Problem:    Error messages are spread out.
Solution:   Move more errors to errors.h.
diff --git a/src/scriptfile.c b/src/scriptfile.c
index 9c8f1ef..7d0c272 100644
--- a/src/scriptfile.c
+++ b/src/scriptfile.c
@@ -1919,7 +1919,7 @@
 
     if (!getline_equal(eap->getline, eap->cookie, getsourceline))
     {
-	emsg(_("E167: :scriptencoding used outside of a sourced file"));
+	emsg(_(e_scriptencoding_used_outside_of_sourced_file));
 	return;
     }
 
@@ -1983,7 +1983,7 @@
     if (getline_equal(eap->getline, eap->cookie, getsourceline))
 	do_finish(eap, FALSE);
     else
-	emsg(_("E168: :finish used outside of a sourced file"));
+	emsg(_(e_finish_used_outside_of_sourced_file));
 }
 
 /*