revset: gratuitous formating fix in keyword You will be aligned.

revset: gratuitous code move in '_children' As 'cs' is empty as the time of the conditional, we can just return an empty 'baseset' and create the variable later.

revset: mark spots that should use 'smartset.min()' Using smartset's min will be significantly faster when the input set can provided an optimised answer. I do not have time to fix all of them but I'm marking the spot.