core(view): warn about the implications of without initializing

[romintomasetti]

This PR describes what Kokkos::WithoutInitialization implies.

[dalg24]

Please do not mix the change of format with editing the actual content in the same PR

[masterleinad]

Please split this pull request up. Either add the changes to initialization first or convert the file first. Also adding another flag in doc/Makefile should be a separate pull request.

[masterleinad]

Suggested change

	For instance, if you need the destructor of your :code:`MyObjectWithDestructor` be called for each element of your :cppkokkos:`View<MyObjectWithDestructor*>`,
	you **should not use** :cppkokkos:`WithoutInitialization`.
	For instance, if the View's value type is not trivially destructible,
	you **should not use** :cppkokkos:`WithoutInitialization` unless you are taking care of calling the destructor manually before the View deallocates its memory.

[romintomasetti]

Much better indeed.

[masterleinad]

Maybe, rather something like

Suggested change

	The reason for that is, since `Kokkos` did not initialize the memory, it cannot know onto which elements of the :cppkokkos:`View` calling the destructor
	of the :code:`value_type` is valid.
	The mental model is that whenever placement new is used to call the constructor, the destructor also isn't called before the memory is deallocated but it needs to be be called manually.

Or omit it with my previous suggestion.

[romintomasetti]

✔️

[ajpowelsnl]

Good instinct to improve this documentation. Cleaning up the WithoutInitialization section is the more actionable suggestion. My comment about "novice" is one for broader consideration.

[ajpowelsnl]

Suggestion: maybe spell out what to do in the case of both trivially and non-trivially destructible data types, maybe even including a couple of simple code-snippet examples. Perhaps also mention a couple of typical use cases where someone would want to use a View WithoutInitialization.

The sentence on line 469 is not clear, and is a little redundant with the immediately preceding statements. It may not be necessary if the previous verbiage were sharpened up, with spelled out use cases and an couple of simple examples.

[crtrott]

I think this is sufficient. I you don't understand the difference between trivially destructible and not trivially destructible you should not use View of Views - i.e. you are a novice and should have skipped this section.

Addressed