A bit of code cleanup (mid-winter spring cleaning)

[matchai]

Description

I've done a bit of housekeeping around the repo:

• Wrap all test arguments with double quotes, as suggested by the fishshell docs

  If the variable is not set, set but with no value, or set to more than one value you must enclose it in double-quotes. For example,test "$x" = "$y". Since it is always safe to enclose variables in double-quotes when used as test arguments that is the recommended practice.

• Give the Travis node version a clearer name
• Break the multi-case test in section_battery into multiple lines

Motivation and Context

Some mid-winter spring cleaning ⛄️

Types of changes

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)

Screenshots (if appropriate):

Nothing functionally new.

How Has This Been Tested?

• [x] I have tested using MacOS
• [ ] I have tested using Linux

Checklist:

• [x] I have checked that no other PR duplicates mine
• [x] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.