New rule: Prefer Unquoted Atoms

[paulo-ferraz-oliveira]

Name

prefer_unquoted_atoms

Brief Description

Prefer unquoted atoms unless quotes are necessary.

Reasoning

This one is not a technical concern, but a readability concern. The code will behave identical in both ways.

Refactoring Proposal

elvis shall warn that your atoms are quoted when they don't have to be.

Note: if you're using a formatter this could/should already be taken into account by it.

Origin

Inspired by Credo's https://hexdocs.pm/credo/Credo.Check.Readability.PreferUnquotedAtoms.html.