Resolve violations of no-useless-escape lint

[miqh]

Hello,

These changes should remove the need to suppress the no-useless-escape lint in eslintrc.json.

I guess worth pointing out is the fact most characters are interpreted literally inside a character class regular expression rule, which is why this lint was complaining.

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Merge / deployment checklist

• Confirm this change is backwards compatible with existing workflows.
• Confirm the readme has been updated if necessary.

[cbraynor]

👍🏼 thanks!