Allow duplicate action-creator names, or warn on their creation.

[Rossh87]

Per the FAQ,

If you have two handler function, handlerOne and handlerTwo, and two components ComponentOne and ComponentTwo, you cannot call useFPReducer in ComponentOne with the handler-mapping object {RUN_HANDLER: handlerOne} and then call useFPReducer in ComponentTwo with the handler-mapping object {RUN_HANDLER: handlerTwo}. If the key RUN_HANDLER is re-used like this and ComponentOne is the first to render in your app, only handlerOne will be associated with the action {type: 'RUN_HANDLER'}. handlerTwo won't be registered with react-use-fp, and dispatching {type: 'RUN_HANDLER'} from ComponentTwo may cause handlerOne to run.

This is not a pit of success. React creates the expectation that the effects of any calls to dispatch will be limited to the state of the component that called useReducer; react-use-fp should honor that expectation. Manually ensuring uniqueness of every key of every handler-mapping object within the application is fragile. react-use-fp should implement some combination of the following behaviors:

1. Warn in dev mode whenever a user tries to register a handler to an action of a duplicate type
2. Panic/break in the above situation
3. Cause a typescript compiler error. Not sure this is possible.
4. Warn/break if a handler 'takes' an action that was dispatched from an inappropriate place
5. Maintain an association between a handler's initiating 'type' and the scope in which it was created, which would make it possible for duplicates to co-exist without problems, but would be tricky to implement without creating a memory leak whenever a component unmounted and re-mounted.