amend: prune replacement commit without sucessors
This align with the core behavior of `commit --amend`.
All user of rewrite are not responsible for creating their own marker.
'''enable experimental obsolescence feature of Mercurial
OBSOLESCENCE IS AN EXPERIMENTAL FEATURE MAKE SURE YOU UNDERSTOOD THE INVOLVED
CONCEPT BEFORE USING IT.
/!\ THIS EXTENSION IS INTENDED FOR SERVER SIDE ONLY USAGE /!\
For client side usages it is recommended to use the evolve extension for
improved user interface.'''
import mercurial.obsolete
mercurial.obsolete._enabled = True