add empty_data option where required option is used
improve explanation of code block for bundle removal and fix typo
add missing code-block directive
add note when forbidding access to anonymous users on custom authentication provider
[Contributing] Clarify the rebase operation

I just mentioned the fact that `push -f` is usually required when rebasing and explicit that the "2.2 when bugfixing" is a follow up on the previous example (Not necessarily explicit at first).
[Contributing] Fix single vs double backtick issues
[Contributing] Add PSR-1 and 2 links
[Contributing] Replace mentions of 2.2 for 2.3

As per WouterJ request: https://github.com/symfony/symfony-docs/pull/3421#issuecomment-31585092
answer some questions and clarify the best chapter imo from the symfony documentation
address comments from @WouterJ
[Reference][Form Types] Document "with_minutes" time/datetime option
Added info about JsonFileLoader added in 2.4
[Contributing] Fix "When you finish" => "When you are finished"

As per @xabbuh suggestion: https://github.com/symfony/symfony-docs/pull/3421#discussion_r8661716
Fix "versionadded" position
add max_length to form field type
Update custom_password_authenticator.rst

Fixed TokenInterface use statement causing compile errors
fix typo in previous commit
fix typo in previous commit
fix last typo on max length option
[Contributing] Replace HEAD~3 by upstream/master

As per @cordoval suggestion: https://github.com/symfony/symfony-docs/pull/3421#discussion_r8670868