omit Sql properties absent from TransactionSql in type definition

[maxcbc]

TransactionSql is missing properties from Sql added in

postgres/src/index.js

Lines 69 to 82 in 32feb25

	Object.assign(sql, {
	get parameters() { return options.parameters },
	largeObject: largeObject.bind(null, sql),
	subscribe,
	CLOSE,
	END: CLOSE,
	PostgresError,
	options,
	reserve,
	listen,
	begin,
	close,
	end
	})

.

This PR updates the type definition of TransactionSql to reflect this.

This means typescript will now raise an error if consuming code tries the following:

sql.begin((trx) => {
   trx.begin((trx2) => {
       ...
   })
})