Fixes #59876

Fixes #60005

Introduces the concept of a re-trigger character to the signature help provider. This is a seperate set of characters that are registered with the provider. Typing a retrigger character fires a new signature help request if signature help is already showing.

#54972

* make actionbar support different trigger keys

* add some undefined checks

The previous solution involved an own solution with an array of
disposables. The new solution makes use of the _register-method from the
Displosable class.

#53989

* enable dynamic menu on linux/windows
workaround to fix #33457

* Address feedback

* other comment

fixes #53989