Summary

Add an RDoc::Task and the rdoc development dependency so contributors can run the documentation coverage check locally:

bundle exec rake rdoc:coverage

This exposes the RDoc documentation coverage task locally. It can help contributors identify documentation coverage issues before changes are synchronized into ruby/ruby.

Changes

• add rdoc as a development dependency
• register RDoc::Task
• expose bundle exec rake rdoc:coverage

Example

$ bundle exec rake rdoc:coverage

100.00% documented

Scope

This change only exposes the existing RDoc task locally.

It does not:

• change the default Rake tasks
• add or modify CI
• introduce any new contributor requirements