Improve js written for guides

* Stop using unnecessary global variable
* Use function defined by jQuery for simplicity
* Fix event listner for "more info button" to handle
  event on resize browser
Add few information about missing steps [ci skip]

Add some deprecations previously note covered such as the confirm
option for the link_to helper or options which aren't needed anymore

Also add a mention about the config.assets.js_compressor option.
Document where `column` param gets utilized in `substitute_at`.
Use helper method to get ENV['CONTENT_LENGTH']
Use Request#raw_post instead Request#body

In order to get raw_post to be not empty after
ParamsParser#parse_formatted_parameters,
added rewinding of body stream input on parsing json params.

Closes #11345
cache.exists? should return true/false
Explicitly test for true and false.
Added cursor pointer for 'More Ruby on Rails'

dropdown menu on guides page (which appear on small windows)
[ci skip]
Fixed broken link of Travis CI for rails and added full path
Remove redundant test about `push_with_attributes` removal.
link break added after the Travis CI link

link break added after the Travis CI link
Merge pull request #11373 from vipulnsward/remove_deprecated_test

Remove redundant test about `push_with_attributes` removal.
Merge pull request #11368 from Amit-Thawait/master

Fixed Travis CI link for rails
Merge pull request #11361 from jetthoughts/add_cursor_pointer_for_menu

Added cursor pointer for 'More Ruby on Rails' dropdown menu on guides page (which appear on small windows)
Merge pull request #11353 from jetthoughts/revert_to_raw_post

Use Request#raw_post instead Request#body in ParamsParser#parse_formatted_parameters
Merge pull request #11351 from jetthoughts/cleanup_request

Use content_length method instead of ENV['CONTENT_LENGTH'].to_i
Merge pull request #11354 from jadeatucker/cache_exists_should_return_boolean

cache.exists? should return true/false
Merge pull request #11143 from robin850/upgrading-rails

Add few information about missing steps [ci skip]
Merge pull request #11073 from tricknotes/improve-guides-js

Improve guides js
Merge pull request #11174 from vipulnsward/remove_column_passing

Stop sending column info to `substitute_at` as it doesn't get utilized.