Type of PR (feature, enhancement, bug fix, etc.)

Bug fix

Description

It doesn't seem like the sanity check modules receive anything in the ARGV, and since it's basically impossible to obtain the CLI command used to run the rake task, I suspect that the called_by_generate_config? method isn't doing anything.

I came up with an admittedly hacky but seemingly effective way to determine if the sanity check is being run inside of rake:

    def called_by_rake?
      caller.find { |c| c.include?("/gems/rake-") }
    end

I have been able to verify that installation works great on a fresh Rails 6.1 project.

I also took the opportunity to freshen up the copy offered by the warning messages. I found it a bit hard to read.

Fixes #508

Install task needs to be rock solid.

Checklist

• My code follows the style guidelines of this project
• Checks (StandardRB & Prettier-Standard) are passing
• This is not a documentation update