Clarify parameters conventions
fix form type.
Example of getting entity managers directly from the container

The documentation didn't provide examples of how to obtain the entity managers directly from the DI container.  This is useful when needing to inject the em into other services.

The ems are added to the container using the service id `doctrine.orm.%s_entity_manager`, where `%s` is the em's name.  This is done by `\Doctrine\Bundle\DoctrineBundle\DependencyInjection\DoctrineExtension::loadOrmEntityManager()` (see: https://github.com/doctrine/DoctrineBundle/blob/v1.2.0/DependencyInjection/DoctrineExtension.php#L347)
Contributions should be based off 2.3 or higher

Per the documentation (http://symfony.com/doc/current/contributing/documentation/overview.html#contributing), the base branch should be 2.3, not 2.2.
Update forms.rst

Hi there, 
I thought it would be nice to specify that you can set a label to false to disable it. I needed it for a project, couldn't find it in the doc, and had to search through a couple of stackoverflow posts to find the solution.
Update forms.rst

not sure what you meant about the wrapping, I applied a soft wrap after "to your input,".
Let me know how that looks
Update forms.rst
Fix typos
Wrap variables in {} for safer interpolation
Fix PSR error
Added CHANGELOG for 2.3
Change interpolation to concatenation
Replace double quotes with single quotes
Fixing typo - thanks to @xabbuh
Add missing variable assignment

Line 41 made use of $crawler which wasn't defined.
Applied comment
Update generic_event.rst

The $event['data'] field was not set, thus it wouldn't be modified.

Also, the example already had a lowercase string. Uppercased 1 letter.
fix referenced documents names
remove empty_data from the list of inherited options, it's documented in the overriden options section
Quick note so that we don't forget to update the branch version stuff in the README file - see #3546