By directly modifying the results array with
`results[i] = "#{name} (installed)"`, it appeared on successive
iterations that the canonical name was no longer in the array, so
aliases were not removed.
See 9efe5b554c (commitcomment-12969631)ClosesHomebrew/homebrew#43433.
This is the (partially) documented public API for Homebrew. It's currently a work in progress. Sorry about that!
The main class you should look at is the {Formula} class (and classes linked from there). That's the class that's used to create Homebrew formulae (i.e. package descriptions). Assume anything else you stumble upon is private.