add --man flag for man page generation

add Taskfile.man.yml
include it in the main Taskfile

add man flag to Flags section in README

go.sum

@@ -1,3 +1,5 @@
+github.com/StevenACoffman/mango-ff v0.0.0-20260411205343-7f039223efef h1:dsNBocAa6MKaCZSZMDWwiFpjZzI7G24lGV/0t+s9SPY=
+github.com/StevenACoffman/mango-ff v0.0.0-20260411205343-7f039223efef/go.mod h1:tvurZfjDXWtWGzD25r9esOSp729MCY96/rtchu+Jx30=
 github.com/aymanbagabas/go-osc52/v2 v2.0.1 h1:HwpRHbFMcZLEVr42D4p7XBqjyuxQH5SMiErDT4WkJ2k=
 github.com/aymanbagabas/go-osc52/v2 v2.0.1/go.mod h1:uYgXzlJ7ZpABp8OJ+exZzJJhRNQ2ASbcXHWsFqH8hp8=
 github.com/charmbracelet/colorprofile v0.4.3 h1:QPa1IWkYI+AOB+fE+mg/5/4HRMZcaXex9t5KX76i20Q=
@@ -33,6 +35,10 @@ github.com/mattn/go-isatty v0.0.21 h1:xYae+lCNBP7QuW4PUnNG61ffM4hVIfm+zUzDuSzYLG
 github.com/mattn/go-isatty v0.0.21/go.mod h1:ZXfXG4SQHsB/w3ZeOYbR0PrPwLy+n6xiMrJlRFqopa4=
 github.com/mattn/go-runewidth v0.0.23 h1:7ykA0T0jkPpzSvMS5i9uoNn2Xy3R383f9HDx3RybWcw=
 github.com/mattn/go-runewidth v0.0.23/go.mod h1:XBkDxAl56ILZc9knddidhrOlY5R/pDhgLpndooCuJAs=
+github.com/muesli/mango v0.2.0 h1:iNNc0c5VLQ6fsMgAqGQofByNUBH2Q2nEbD6TaI+5yyQ=
+github.com/muesli/mango v0.2.0/go.mod h1:5XFpbC8jY5UUv89YQciiXNlbi+iJgt29VDC5xbzrLL4=
+github.com/muesli/roff v0.1.0 h1:YD0lalCotmYuF5HhZliKWlIx7IEhiXeSfq7hNjFqGF8=
+github.com/muesli/roff v0.1.0/go.mod h1:pjAHQM9hdUUwm/krAfrLGgJkXJ+YuhtsfZ42kieB2Ig=
 github.com/muesli/termenv v0.16.0 h1:S5AlUN9dENB57rsbnkPyfdGuWIlkmzJjbFf0Tf5FWUc=
 github.com/muesli/termenv v0.16.0/go.mod h1:ZRfOIKPFDYQoDFF4Olj7/QJbW60Ol/kL1pU3VfY/Cnk=
 github.com/pelletier/go-toml/v2 v2.3.0 h1:k59bC/lIZREW0/iVaQR8nDHxVq8OVlIzYCOJf421CaM=