Ensure that all the new window-function keywords can still be used as SQL identifiers.

FossilOrigin-Name: a6d61dfd4780eccfce5f7a5ead6c04e3b78bc4a461551fd7dd602550e0d51084

src/parse.y

@@ -218,6 +218,7 @@ columnname(A) ::= nm(A) typetoken(Y). {sqlite3AddColumn(pParse,&A,&Y);}
 %endif SQLITE_OMIT_COMPOUND_SELECT
 %ifndef SQLITE_OMIT_WINDOWFUNC
   CURRENT FOLLOWING PARTITION PRECEDING RANGE UNBOUNDED
+  EXCLUDE GROUPS OTHERS TIES
 %endif SQLITE_OMIT_WINDOWFUNC
   REINDEX RENAME CTIME_KW IF
   .