Fixing the two instances of "rU"

[colinmford]

Description

Replaces the two instances of "rU" with "r", as python now deals with newlines by default since Python 3.4. Fixes #1583

Checklist:

• I have followed the Contribution Guidelines
• [-] I have added test code and data to prove that my code functions correctly
• I have verified that new and existing tests pass locally with my changes
• I have performed a self-review of my own code
• [-] I have commented my code, particularly in hard-to-understand areas
• [-] I have made corresponding changes to the documentation

[josh-hadley]

This looks good to me. The Windows build is failing (and has been for a while) for reasons unrelated to this PR so no concerns about that.

[colinmford]

@josh-hadley @frankrolf so we're good for a merge on this?

[frankrolf]

I guess so! ¯_(ツ)_/¯