Close #741 Option to disallow dups in prompt hist
Close #741 Option to disallow dups in prompt hist

Implement option in `prompt.py` widget to implement the
`HIST_IGNORE_ALL_DUPS` or `HIST_IGNORE_DUPS` option, present
in some shells/DEs/WMs, for not duplicating entries into the
history record.

soulchainer/qtile,cortesi/qtile,flacjacket/qtile,frostidaho/qtile,kynikos/qtile,qtile/qtile,zordsdavini/qtile,flacjacket/qtile,ramnes/qtile,de-vri-es/qtile,de-vri-es/qtile,ramnes/qtile,kynikos/qtile,soulchainer/qtile,frostidaho/qtile,cortesi/qtile,qtile/qtile,tych0/qtile,tych0/qtile,zordsdavini/qtile