[ticket/12895] Rename user style setting to resolve conflict with style param

The style URL parameter, i.e. style=1, will conflict with the user's style
setting due to it also being named style. This patch with solve this conflict.

PHPBB3-12895
[ticket/12902] Remove duplicate entry in switch statement

PHPBB3-12902
Merge branch 'ticket/JeroenDeDauw/12902' into develop-ascraeus

* ticket/JeroenDeDauw/12902:
  [ticket/12902] Remove duplicate entry in switch statement
Merge pull request #2782 from marc1706/ticket/12895

[ticket/12895] Rename user style setting to resolve conflict with style param

* marc1706/ticket/12895:
  [ticket/12895] Rename user style setting to resolve conflict with style param
[ticket/12908] Fix operator typo in increment.php

PHPBB3-12908
[ticket/12909] Use correct lang vars in cli extension enable

PHPBB3-12909
Merge pull request #2792 from n-aleha/ticket/12908

[ticket/12908] Fix operator typo in increment.php

* n-aleha/ticket/12908:
  [ticket/12908] Fix operator typo in increment.php
Merge pull request #2793 from n-aleha/ticket/12909

[ticket/12909] Use correct lang vars in cli extension enable

* n-aleha/ticket/12909:
  [ticket/12909] Use correct lang vars in cli extension enable
[ticket/12906] Add rel="help" to FAQ link

PHPBB3-12906
Merge pull request #2796 from bantu/ticket/12906

[ticket/12906] Add rel="help" to FAQ link

* bantu/ticket/12906:
  [ticket/12906] Add rel="help" to FAQ link