patch 8.2.1269: language and locale code spread out

Problem:    Language and locale code spread out.
Solution:   Move relevant code to src/locale.c. (Yegappan Lakshmanan,
            closes #6509)
diff --git a/src/proto.h b/src/proto.h
index e3a25f9..95fd81a 100644
--- a/src/proto.h
+++ b/src/proto.h
@@ -101,6 +101,7 @@
 # include "insexpand.pro"
 # include "json.pro"
 # include "list.pro"
+# include "locale.pro"
 # include "blob.pro"
 # include "main.pro"
 # include "map.pro"