yard-junk: Yard documentation quality checks

[zverok]

Project

yard-junk is already established and production-used solution for checking the quality of YARD documentation of Ruby projects.

The current version only checks for errors is documentation (misused tags and such), but the next step would be to introduce Rubocop-style flexible quality checks, allowing to establish and maintain per-project preferred documentation style.

Plan

The plan is briefly discussed in this GitHub issue.

1. Establish some "plugin architecture" for checks.
2. Develop several new documentation quality checks incrementally.
3. Work on configuratibility of checks.
4. Work on usability of command-line tool and flexibility of its output.

Importance

YARD is the de-facto standard of Ruby documentation (alongside with RDoc, but yard as a tool supports RDoc too, so yard-junk can be useful for checking virtually any Ruby project's docs). Establishing a tool for docs quality checking (and auto-fixing if possible) seems to be of general use.

Skills and domains

While working on it, you'll need dive really deep into YARD tool internals, and create modular and pluggable architecture like Rubocop with its cops.