* Introducing a new type of exception and a new hospital staff member to pause flows by immediately hospitalising them.
* Renaming exception to "HospitalizeFlowException".
* Making HospitalizeFlowException an open class.
* Overloading constructors of HospitalizeFlowException to be available in Java.
* Using Throwable#mentionsThrowable.
* Moving HospitalizeFlowException in its own file.
* Update kdocs for HospitalizeFlowException and StaffedFlowHospital#SedationNurse.
* Added tests, testing various HospitalizeFlowException types thrown.
* Fix Detekt issues.
* Imports optimizing.
* Add safe casting.
* Update api-flows and node-flow-hospital docs.
* Minor code comment change.
* Add DOCSTART-DOCEND signs in HospitalizeFlowException for makeDocs. It is referenced by api-flows.rst.
* Minor change in note.
* Code formatting.
* Remove comment.
* Remove if statement that makes example worse.
* Remove redundant comment.
* Moving 'Internal Corda errors' at the bottom.
* Changing node-flow-hospital.rst as per review.
* Change HospitalizeFlowException description as per review.
* Adding an example for FlowException.
* Minor indentation fix.
* Update FlowException example label as per review.
* Correcting handling of custom exception.
