[forms] Remove tip for skipping validation group section
Update installation.rst

typo in cookbook/bundle/installation
add missing word
Added missing tilda (yml config)

The tilda was missing for the YAML configuration.
Merge branch '2.0' into 2.1
Fixed build
Some minor fixes
remove obsolete note on monolog.logger tag
added a missing security advisory
Merge branch '2.0' into 2.1
Merge pull request #2987 from greg0ire/missing_word

add missing word
Merge branch '2.0' into 2.1
Merge pull request #2991 from WouterJ/build_error

[2.1] Fixed Build errors
Merge pull request #3006 from havvg/2.1

remove obsolete note on monolog.logger tag
Add note about PHP 5.3 behaviour and proxies.
Better wording.
Merge pull request #2981 from bicpi/remove_tip_for_validation_groups

[forms] Remove tip for skipping validation group section
Merge branch '2.0' into 2.1
Merge pull request #2984 from peterkokot/2.1

Update installation.rst
Merge pull request #2997 from WouterJ/fix_form_component

Fixes for Form Component chapter