Exclude MissingTranslation options that are not used by the instance

[sundling]

Fixes #580

Instances of MissingTranslation are currently initialized with the options originally passed to I18n.translate.
When using ActiveRecord those options will include a reference to the instance.
And when combined with a (Rails) cache store, that MissingTranslation instance is now expected to work with Marshal.dump.

The only MissingTranslation option being used appears to be :scope; when converting the instance to a string, so that key is kept.

[radar]

Thanks for this PR @sundling. Could you please add a description to show what drove this change?

[simonlevasseur]

This PR recently introduced an issue for us in a scenario where we were catching MissingTranslation errors and re-invoking I18n.translate with a different locale but reusing the key and options. Doing that now results in a translation without the proper variables for interpolation.

I think from a convention POV, it makes sense to pass the options back via the exception. The bug that we are trying to fix in this PR is pretty specific to Rails/ActiveRecord but the change was made globally which is unexpected.

Can we revert and apply a more narrow fix in ActionRecord?

[radar]

@simonlevasseur Yes, I think that would be a sensible approach here.

[simonlevasseur]

Just to clarify, do you want me to revert this PR or do you plan on doing it?

[radar]

@simonlevasseur could you please look into it?

[xtreme-shane-lattanzio]

I think we may be running into issues with this as well. Since 1.9.0 we are getting I18n::InvalidLocaleData: can not load translations from /usr/share/rvm/gems/ruby-2.7.1/gems/activesupport-6.0.4.4/lib/active_support/locale/en.yml: #<ArgumentError: wrong number of arguments (given 2, expected 1)>

[radar]

@xtreme-shane-lattanzio please open a new issue here with a link to a repo that reproduces this issue

[xtreme-shane-lattanzio]

I think something was weird with including an of safe_yaml gem. We removed it and the error went away since we should be using YAML.safe_load instead of SafeYAML.load anyway