Exercise hash_exercises.rb: rename favorite_list to favorite_hash for clarity

[sometimescasey]

Because

favorite_hash is a less ambiguous parameter name

This PR

• renames all instances of favorite_list to favorite_hash in hash_exercises.rb
• and analogously, renames original_list and additional_list

Issue

Closes #96

Additional Information

Pull Request Requirements

• I have thoroughly read and understand The Odin Project Contributing Guide
• The title of this PR follows the location of change: brief description of change format, e.g. Data types exercise: Update spec files
• The Because section summarizes the reason for this PR
• The This PR section has a bullet point list describing the changes in this PR
• If this PR addresses an open issue, it is linked in the Issue section
• If this PR includes changes that needs to be updated on the solutions branch, I have created another PR (and linked it to this PR).

[JoshDevHub]

This is a nice change. Thanks for making it. Definitely agree that using hash makes things a bit more clear, especially for people who may have some familiarity with languages that have a List type (python, C#, and so on).

Sorry it took several weeks for us to get around to reviewing it.

One quick thing I wanted to ask @sometimescasey : this repo has a solutions branch that holds the answers to all of the exercises. You can view it here. Would you be okay making another quick PR that makes the same changes to that branch?

If you don't want to, that's okay and we can put someone else on it. Just let me know.