patch 8.2.3749: error messages are everywhere

Problem:    Error messages are everywhere.
Solution:   Move more error messages to errors.h and adjust the names.
diff --git a/src/bufwrite.c b/src/bufwrite.c
index 76c36e1..035c859 100644
--- a/src/bufwrite.c
+++ b/src/bufwrite.c
@@ -713,7 +713,7 @@
     // Avoid a crash for a long name.
     if (STRLEN(fname) >= MAXPATHL)
     {
-	emsg(_(e_longname));
+	emsg(_(e_name_too_long));
 	return FAIL;
     }