Re: COPY (... tab completion

I think this would be a useful addition.  A couple of problems:

This change in the comment doesn't make sense to me and doesn't seem to
match the code:

-    /* If we have COPY [BINARY] <sth>, complete it with "TO" or "FROM" */
+    /* If we have COPY|BINARY <sth>, complete it with "TO" or "FROM" */

The list of commands to allow as the "query" inside the parentheses is
documented to be: SELECT, VALUES, INSERT, UPDATE or DELETE; and actually
TABLE should also work.  Your list doesn't include all of those.  So
please adjust that.