call-seq directive makes rdoc cry and replaces method names with a curly brace; besides it doesn't add anything when you only list one call example since this is obviously documented already

Fix capture_helper.rb api documentation, unescaped script tag was breaking it on the content_for explanation

Fix capture_helper.rb api documentation, unescaped script tag was breaking it on the content_for explanation

This reverts commit 7a6d8e4a.

Reason: The method that gives you a Ruby string with JSON source code is #to_json

Signed-off-by: NXavier Noria <fxn@hashref.com>

This information was lost in commit bd6b61be.
This might have been intentional, but this class does represent the starting
point for all things related to actions, and as such should document it.

I couldn't find any trace of this documentation, which seems like a waste.
Updated parts here and there to conform to current best practices.

Signed-off-by: NXavier Noria <fxn@hashref.com>