Cask update error msgs

[narendasan]

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This PR should address Homebrew/homebrew-cask#25127

The message printed when brew cask errors out has been changed from a generic command to pointing at the brew cask documentation on github so that instructions can be changed outside of brew.

There are 2 questions that I have (that should not effect this PR):

• Should https://github.com/Homebrew/brew/blob/master/Library/Homebrew/cask/lib/hbc/artifact/base.rb#L52
  https://github.com/Homebrew/brew/blob/master/Library/Homebrew/cask/lib/hbc/artifact/uninstall_base.rb#L90 be changed as well?
• brew cask-tests fails on the version test, but it does that on master as well. Is this a known issue?

[jawshooah]

This empty line can go.

[narendasan]

Without the newline the error message and the instructions get concatenated together. Would it be better to change line 155 in cli.rb to add a newline to the end of the error message?

[jawshooah]

Yes, that sounds like more of an issue with the call site than with the message itself.

[reitermarkus]

I'd use “Follow” instead of “Try following”.

[jawshooah]

@narendasan I cleaned up your branch to try and fix the CI errors, but it looks like it didn't work. You'll need to git pull --rebase to bring your branch up to date and address @reitermarkus's comment.

[narendasan]

I have the required tests working but I am not sure what I need to modify for the codecov checks to pass