Complete SELECT output aliases in ORDER BY and HAVING #1

Local SQL completion does not recognize output aliases declared by the current SELECT when writing ORDER BY or HAVING.

For example, with an orders table containing an amount column:

SELECT SUM(amount) AS total_revenue
FROM orders
ORDER BY tot

The editor should offer total_revenue at the end of tot. The same alias should be available in HAVING, while aliases from other statements, nested SELECTs and CTEs must not leak into the current scope.

This concerns local editor suggestions only; query execution does not need to change.