Improve tab completion for ALTER DEFAULT PRIVILEGE and ALTER TABLE

Hi,

Improved tab completion for "ALTER DEFAULT PRIVILEGE" and "ALTER TABLE":
1) GRANT, REVOKE and FOR USER keyword was not displayed in tab
completion of alter default privileges like the below statement:
ALTER DEFAULT PRIVILEGES GRANT INSERT ON tables TO PUBLIC;
ALTER DEFAULT PRIVILEGES REVOKE INSERT ON tables FROM PUBLIC;
ALTER DEFAULT PRIVILEGES FOR USER vignesh revoke INSERT ON tables FROM dba1;

2) USER was not displayed for "ALTER DEFAULT PRIVILEGES IN SCHEMA
public FOR " like in below statement:
ALTER DEFAULT PRIVILEGES IN SCHEMA public FOR USER dba1 GRANT INSERT
ON TABLES TO PUBLIC;

3) "FOR GRANT OPTION" was not display for "ALTER DEFAULT PRIVILEGES
REVOKE " like in below statement:
alter default privileges revoke grant option for select ON tables FROM dba1;

4) "DATA TYPE" was missing in "ALTER TABLE table-name ALTER COLUMN
column-name SET" like in:
ALTER TABLE t1 ALTER COLUMN c1 SET DATA TYPE text;

Attached patch has the changes for the same.

Regards,
Vignesh