Add 'ordinality' and 'unnest' keywords

These are for the Unnest feature, still under review

Author: javier

src/grammar/keywords.ts

@@ -120,6 +120,7 @@ export const keywords: string[] = [
   "option",
   "or",
   "order",
+  "ordinality",
   "others",
   "outer",
   "over",
@@ -186,6 +187,7 @@ export const keywords: string[] = [
   "unbounded",
   "union",
   "unlock",
+  "unnest",
   "unpivot",
   "update",
   "upsert",