This PR was submitted for the 3.0 branch but it was merged into the 2.3 branch instead (closes#6472).Discussion----------Avoid confusionTo me it was a bit confusing why the locale was set on the session and not the request. Further more, reading the linked article shows extra code is needed to make this work at all.Since the linked article explains in more detail how to make the locale sticky, I suggest just setting it on the request in this code sample.Commits-------6818b8e Avoid confusion

* 2.3:  [#6472] Updating description, after change  Avoid confusion  Added file paths  Fixes and rewords  Documented the config options of TwigBundle  [#6427] Adding a header  Tests: Explain how to add or remove data in a collection of forms  Document constraint validator alias optional

* 2.7:  [#6472] Updating description, after change  Avoid confusion  Added file paths  Fixes and rewords  Documented the config options of TwigBundle  [#6427] Adding a header  Tests: Explain how to add or remove data in a collection of forms  Document constraint validator alias optional

* 2.8:  [#6472] Updating description, after change  Avoid confusion  Added file paths  Fixes and rewords  Documented the config options of TwigBundle  [#6427] Adding a header  Tests: Explain how to add or remove data in a collection of forms  Document constraint validator alias optional

* 3.0:  [#6472] Updating description, after change  Avoid confusion  Added file paths  Fixes and rewords  Documented the config options of TwigBundle  [#6427] Adding a header  Tests: Explain how to add or remove data in a collection of forms  Document constraint validator alias optional