…viereguiluz)This PR was merged into the 3.2 branch.Discussion----------Mentioned %env(...)% variables in Best Practices bookCommits-------91096ec Mentioned %env(...)% variables in Best Practices book

* 3.2: (22 commits)  add missing config formats  [#7224] fix indentation  [#7220] some minor tweaks  [#7196] add versionadded directive  Explained how to improve the readability of long numeric literals  Fix typo in workflow usage code lock  Added "How to Use a Custom Version Strategy for Assets"  Use PHP 5.5's ::class notation  Update state-machines.rst  [PHPUnitBridge] Fix copy/paste error  [PHPUnitBridge] Fix copy/paste error  [#7243] minor tweak  Deletes duplicate "Deprecated" and adds a more explicit example.  Accepted Suggestions  Update 'query_builder' option  Mentioned %env(...)% variables in Best Practices book  Accepted suggestions in the guard documentation  Accepted suggestions in the guard documentation  Accepted suggestions in the guard documentation  Update guard_authentication.rst  ...