Remove unnecessary comments in cache_helper.rb [ci skip]

[kenta-s]

I looked into a TODO comment in cache_helper.rb.

I think we can remove those comments.

the comments were added in this commit: 9de8305

Below is a pic of the commit opened in RubyMine.

I guess he left the comment because he thought capture method would be able to work by its own without 'the dance' in his future.

I git-reseted to see the code at the time. The methods named capture were in ActionView::Helpers::CaptureHelper(which exists in current master branch, too) and Rails::Generators::TestCase. in this case, it is obvious that he meant the first one.

Now, we can use capture not only in erb, but builder and jbuilder with no problem even without write_fragment_for.

From these reasons, those long lived comments can go.

To be honest, I'm not 100% sure the intention of his comments.
Please let me know if there is someone who knows what he meant, and who thinks I'm wrong. If so, I want to try to deal with it.

Personally, I don't think it is a good idea to ignore TODO comments such a long time(6 years in this case).

[rails-bot]

r? @rafaelfranca

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[kaspth]

Funnily enough, we did run into this last year on rails/jbuilder#341 (comment).

But definitely agreed that we may as well remove the comments. Thanks for the investigation!