Fixed namespace separator
Update dic_tags.rst

  SwiftMailer plugin works only if its service defined with tag 'swiftmailer.default.plugin' and does not work with tag 'swiftmailer.plugin' specified in documentation
Update dic_tags.rst
Update dic_tags.rst
Update dic_tags.rst
add documentation for configuring additional monolog channels
fix the XML config and add the corresponding PHP config
Simplified "Ensuring the database persistence" example
[Cookbook][Security] Update Voters: add class properties
Simplified "Ensuring the database persistence" example

corrections
fixed repeated verb in cookbook/serializer
executable permissions unset
add missing verb in cookbook/serializer
[Cookbook][Bundles][Remove] Fix a broken link to the API
image tag for assetic management added and fixed a typo
Merge pull request #3199 from szjani/patch-1

Fixed namespace separator
[#3199] Making format tweaks suggested by @WouterJ
Merge pull request #3201 from mgrinko/patch-1

DI-tags documentation should contain 'swiftmailer.default.plugin' tag instead of 'swiftmailer.plugin' to work
[#3201] Minor language tweak to clarify why you might have this situation
Merge branch '2.3' into 2.4