Fix documentation for grouped_collection_select [ci skip]
Removed "to:" from root directive and fixed typo ":to"

`root :to` is invalid syntax
`root to:` is valid, but the generated routes file omits `to:`
Re-remove deprecated API.
Merge pull request #11145 from JeffreyRodriguez/rails_4_root_directive_updates_and_fixes

Removed "to:" from root directive and fixed typo ":to"
Merge pull request #11146 from kennyj/re-remove-deprecated-api

Re-remove deprecated API.
Merge pull request #11141 from keydunov/master

Fix documentation for grouped_collection_select
Remove passing the prompt to grouped_options_for_select as an argument, because it was deprecated.
Merge pull request #11147 from kennyj/remove_prompt_argument_was_deprecated

Remove passing the prompt to grouped_options_for_select as an argument, because it was deprecated.
Remove deprecated attr_protected/accessible

Rails 4.0 has removed attr_protected and attr_accessible feature in favor of Strong Parameters.
Review AV changelog [ci skip]
Merge pull request #11149 from strzalek/remove-protected-attrs

Remove deprecated attr_protected/accessible