[hail][build] ignore generated docs files (#8797)
[hail][build] ignore generated docs files (#8797)

Not sure why these are not already ignored. They seem to get created when I
run `./gradlew install-editable`.
danking/hail,hail-is/hail,cseed/hail,cseed/hail,danking/hail,danking/hail,danking/hail,hail-is/hail,danking/hail,hail-is/hail,hail-is/hail,cseed/hail,hail-is/hail,hail-is/hail,cseed/hail,cseed/hail,cseed/hail,danking/hail,hail-is/hail,cseed/hail,cseed/hail,hail-is/hail,danking/hail,danking/hail