Bug#1115339: explain `-rem alla` and `-rem allb` in the help and in the man pages

[Peter Müller]

Package: pngcrush
Version: 1.8.13-2~exp1


The documentation leaves a small but rather curious gap: neither the manual pages (`man pngcrush`) nor the built-in help (`pngcrush --help`) explain what the mysterious arguments `alla` and `allb` mean when passed to the `-rem` option.

Examples:
     pngcrush -rem alla input.png output.png
     pngcrush -rem allb input.png output.png

Currently, the only way to discover their meaning seems to be consulting the Internet, or worse, reading the source code. It would be wonderful if users could instead learn this from the locally installed documentation, as with other options.

I do know an *Alla*, but I'm quite sure she wouldn't appreciate being removed from a PNG file. As for *Allb*, I've never met them, except, perhaps, an overweight Al(ex) heavy on lb . :-)

Gratefully,
Peter