* query_as: don't stop stream after decoding error
Fixes https://github.com/launchbadge/sqlx/issues/1884
When a single row cannot be converted to the target type of query_as,
it should not prevent the library user from accessing the other rows
Otherwise, the user cannot access all query results in query_as.
* use union in tests to maximize db compatibility
* Make it possible to use both nullability and type overrides
* Fix override parsing lookahead logic
* Update column override tests
* Support nullability overrides with wildcard type overrides
* Fix tests
* Update query! overrides docs
* Remove last bits of macro_result!
* rustfmt
