Improve handling of constants that are just aliases

[ccutrer]

• In the constant summary, link to its target object
• When linking from other locations, link directly to the target.

Completed Tasks

• [x] I have read the [Contributing Guide][contrib].
• [x] The pull request is complete (implemented / written).
• [x] Git commits have been cleaned up (squash WIP / revert commits).
• [x] I wrote tests and ran bundle exec rake locally (if code is attached to PR).