[ticket/11233] prohibit selecting anonymous user as a PM recipient

While composing pm, it should not be allowed to add
anonymous user as a PM recipient

PHPBB3-11233
Merge remote-tracking branch 'dhruvgoel92/ticket/11233' into develop-olympus

* dhruvgoel92/ticket/11233:
  [ticket/11233] prohibit selecting anonymous user as a PM recipient
Merge branch 'develop-olympus' into develop

* develop-olympus:
  [ticket/11233] prohibit selecting anonymous user as a PM recipient
[ticket/11220] Improvement to the info pop-up from "list="

A improvement to the info popup which is displayed when the cursor
is over the bbcode-button [list=] in the posting-editor

PHPBB3-11220
Merge remote-tracking branch 'Crizz0/ticket/11220' into develop-olympus

* Crizz0/ticket/11220:
  [ticket/11220] Improvement to the info pop-up from "list="
Merge branch 'develop-olympus' into develop

* develop-olympus:
  [ticket/11220] Improvement to the info pop-up from "list="