Fix window functions with no input channels
Add missing calls to declarePosition

Also, validate that blocks have the same number of positions as the
declared positions in the page to catch these issues in the future
Fix PageBuilder.isEmpty()

It was relying on BlockBuilderStatus.isEmpty, which tracks size.
Entry size can be 0 under certain conditions, which causes PageBuilder
to say it's empty when it's not.
Show empty rows for Values in explain
Fail task when local planning fails
Add release note for JOIN bug
Add release notes for 0.89
Update to airlift 0.99
Update to tpch 0.4
[maven-release-plugin] prepare release 0.89
[maven-release-plugin] prepare for next development iteration
CAST to UNKNOWN should not be allowed
Added map_agg aggregation function
Use checkCondition for approx_distinct
Use HTTPS for documentation links to Maven Central
Add download link for benchmark-driver
Use direct references to top-level documents
Remove duplicate function documentation
Improve documentation for map_agg
Fix formatting for benchmark-driver documentation