Add missing help texts

[vxsx]

this is a wip PR to add all the help texts so autocompletion could just use lancet _arguments command for everything @GaretJax do you want me to put the zsh completion file somewhere in the project as well or should I still keep it here?

[GaretJax]

@vxsx we might merge it somewhen (the completion file, that is), but I want to setup a command to load the whole file as I did for _setup_helper.

[vxsx]

@GaretJax I was poking around in the code and it seems like some things would be a bit hard to do complete automatically (well, I don't have sufficient knowledge of zsh autocompletion possibilities/syntax ofc). Also calling lancet _arguments $command is a quite slow compared to hardcoded version, so maybe we could inline these on lancet _autocomplete call or something. Not sure how to correctly update this autocompletion file on lancet update afterwards, though, but that's something else.

Help texts are ready, please take a look, if you have any corrections or anything. I'd like to squash before/if you're gonna merge.

[GaretJax]

While generating the whole file with inlined commands may be a solution, we could also look into ZSH autocompletion caching. (http://zsh.sourceforge.net/Doc/Release/Completion-System.html search for use-cache)

[vxsx]

@GaretJax can we merge this one? zsh completion improvements will follow in separate PR

[GaretJax]

:+1: