patch 8.2.3967: error messages are spread out

Problem:    Error messages are spread out.
Solution:   Move more errors to errors.h.
diff --git a/src/insexpand.c b/src/insexpand.c
index d006135..1051ae1 100644
--- a/src/insexpand.c
+++ b/src/insexpand.c
@@ -2960,7 +2960,7 @@
     {
 	if (argvars[0].v_type != VAR_LIST)
 	{
-	    emsg(_(e_listreq));
+	    emsg(_(e_list_required));
 	    return;
 	}
 	what_list = argvars[0].vval.v_list;
@@ -4696,7 +4696,8 @@
     {
 	edit_submode_extra = (compl_cont_status & CONT_ADDING)
 			&& compl_length > 1
-			     ? (char_u *)_(e_hitend) : (char_u *)_(e_patnotf);
+				? (char_u *)_(e_hitend)
+				: (char_u *)_(e_pattern_not_found);
 	edit_submode_highl = HLF_E;
     }