Improve Flux HelpPrinter content

[fsteeg]

This is part of metafacture/metafacture.github.io#10

Improve content of HelpPrinter.java:

• Group commands by type (Readers, Decoders, Encoders, Writers)
• Explain signatures (a general explanation about how to read signatures like String -> StreamReceiver or specific translations like "Reads from a string and writes to a stream receiver" or "Expects strings as input and produces metadata events")
• Add missing options

[TobiasNx]

It would be nice if you link to the code of a function too
.

[blackwinter]

Could you elaborate a little?

Group commands by type

What is a command's type?

Explain signatures

What might such an explanation look like?

Add missing options

Which options are missing?

I would maybe add:

• Sort options alphabetically
• List signature before options
• Add (mandatory and optional) arguments via Class.getConstructors() (instead of @ReturnsAvailableArguments annotation?)

And as a slight variation of @TobiasNx's suggestion:

• Link to class's Javadoc
• Maybe even: Link to option's (i.e., setter's) Javadoc

[fsteeg]

Could you elaborate a little?

I've added some details to the original issue description.

[blackwinter]

@dr0i: You checked the task for "Link to class's Javadoc" in my comment, but the recent changes (#509) only link to the source code, not the Javadoc.

[dr0i]

@blackwinter oh, right - I thought of the javadoc comments in the classes...

[dr0i]

See metafacture/metafacture-documentation#52 for grouping/filtering.