Add links to the query api page in view and find --help

[cbkerr]

Description

Adds plaintext links to the output of signac view --help and signac find --help

Motivation and Context

I and others often can't find the query api page from the docs about finding and viewing.

Tested by building locally.

Checklist:

• I am familiar with the Contributing Guidelines.
• I agree with the terms of the Contributor Agreement.
• My name is on the list of contributors.
• The changes introduced by this pull request are covered by existing or newly introduced tests.
• The package documentation and framework documentation in signac-docs are up to date with these changes.
• I have updated the changelog and added any related issue and pull request numbers for future reference.

[bdice]

I think it could be helpful to use some intentional line breaks in this message. I looked at man pages for a few executables and commands like apt search --help, docker run --help and including line breaks is very common for longer descriptions like this. I'd recommend the following:

Filter arguments may be provided directly as JSON or in a simplified form using the query API. For, example the following two bash commands are equivalent:

$ signac find key 42
$ signac find '{"a": 42}'

For more information, see: https://docs.signac.io/en/latest/query.html#simplified-filter

Note that we have an anchor in the source that can be used to shorten this URL: https://github.com/glotzerlab/signac-docs/blame/ddd4a06b23f82b722303d31b3d1eb7338a2fcd97/docs/source/query.rst#L251

I'd do something similar for the other case, too. This is helpful, thanks!

[cbkerr]

Good idea. The included argparse.RawDescriptionHelpFormatter and argparse.RawTextHelpFormatter don't allow wrapping of some text while preserving blank lines. There is a long running feature request for a better formatter for argparse.

I propose adding a new dependency argparse-formatter and its FlexiFormatter, which has been proposed for inclusion in Python, until it gets merged.

See the source of the formatter for docs.

[bdice]

@cbkerr For some context: you may have observed from making this PR that argparse has some undesirable and awkward nuances in its design, and I think many Python developers feel the same way about it. However, it's the only real option we have in the standard library (forgoing the deprecated optparse). The most popular package beyond the standard library for CLI design is click. Previous efforts to rewrite signac's CLI using click stalled because of some nuances in the signac CLI that click didn't support. See conversations on #309. We might be able to adopt click in signac 2.0, if someone is passionate about doing that, but it has not been a high priority task in the past.