Add or update tables specifications links
diff --git a/src/hb-ot-layout-gpos-table.hh b/src/hb-ot-layout-gpos-table.hh
index 46ffcc6..6251707 100644
--- a/src/hb-ot-layout-gpos-table.hh
+++ b/src/hb-ot-layout-gpos-table.hh
@@ -1497,7 +1497,8 @@
 typedef OffsetListOf<PosLookup> PosLookupList;
 
 /*
- * GPOS -- The Glyph Positioning Table
+ * GPOS -- Glyph Positioning
+ * https://docs.microsoft.com/en-us/typography/opentype/spec/gpos
  */
 
 struct GPOS : GSUBGPOS