Add docs clarifying list-doc and install-doc

[rectalogic]

Fixes #753

[ddalcino]

Thank you for the PR! This is definitely an improvement.

Please see the suggested changes below. These are my initial thoughts on how to make this section a little more clear; they are not perfect, but I'll bet we can collectively come up with something better.

[rectalogic]

@ddalcino thanks. So one thing I noticed is list-doc does not accept --archives. So for example the qtmultimedia module consists of 2 archives - qtmultimedia and qtspatialaudio.

So if I only want the qtmultimedia docs, I need to do install-doc mac 6.6.1 --modules qtmultimedia --archives qtmultimedia - if I just do install-doc mac 6.6.1 --modules qtmultimedia then it installs all the default archives plus qtmultimedia and qtspatialaudio docs.

But I don't see a way to figure this out from list-doc. I would just have to install --modules qtmultimedia and realize it is installing multiple modules, then run it again filtering down the archives I guess.

So basically the archives that make up a module are hidden from list-doc - it can only show the default set of archives, or the list of modules. But not the archives that a module consists of.

[ddalcino]

You are correct. In general, there is only a single archive for each module, except for the base module and the debug_info module, which only exists for some platforms when installing Qt (not src/doc/examples).

There are a few edge cases, like this one, where a module contains 2 or more archives.

The purpose of the --archives command is really to help reduce download times and data usage, and I think it does that well enough. I don't think it's worth the maintenance cost to enable it for a couple edge cases here to save a couple kilobytes.

You're welcome to document this as well if it really bothers you.

[pzhlkj6612]

Wording wording.

[miurahr]

Confirmed suggested wording improvements.

[pzhlkj6612]

A GitHub pro tip for @rectalogic:

We are able to apply a batch of changes during code reviewing: Incorporating feedback in your pull request - GitHub Docs.

[pzhlkj6612]

I didn't test the code, but have read the docs. It looks OK to me.

[ddalcino]

LGTM. I ran the code and it does exactly what the code-block sections say they will.