* Improve our deepening logic
* Use consistent SHA for PR-related operations in CheckoutPrTool
* compute `deepenDepth` at more appropriate time
* fix stale comment
* add comments for `alreadyOnBranch`
* ensure before sha is available
* small cleanup
* computeIncrementalDiff
* move the util
* improve algorithm
* improve algorithm further
* get rid of temp result array
* add comment
* compute incremental diff and updte instructions
* add comment
* update stale comment
* get rid of redundant rev-parse call
* improve comment
* strenghten the instructions
* make diff paths unique
Mateusz Burzyński