Fix the "doctrine file uploads" cookbook examples, see symfony/symfony-docs#600
cs fixes
more cs fixes
add missing space
end short descriptions in PHPdoc comment with a .
add some minor interpunction fixes for consistency
fix delete the old image before the move of new image because of the same name
Fixed highlighting issues in The Book
Added PR title prefixes
Added information about currency format
Add a clarification to the event subscriber section

It's not explicitly clear that a higher priority number means the method is called earlier. Add some verbiage to that effect.
Fix two minor typos in the contributing section
[2.0] Re-working some language in the contributing doc to work now that we have 2.0, 2.1, 2.2 and master
[Typo] Fixing typo in date_format form option description
[#2290] Single command apps with arguments

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | all
| Fixed tickets | #2290
add description of doctrine event subscriber and hint on difference between symfony and doctrine event subscriber
layout fixes
Updated link to correct twig docs
Fix DomCrawler html dumping example.
Add missing space in DomCrawler example.