I am confused precisely on the nature of your question, but it sounds like you want simple documentation, furthermore, you are inquiring if Unity has something like Intellisense, That i do not know… I am looking to give you a quick reply, because it has been two hours, but i will look into this for you.
This is the Unity manual 2017.1 (https://docs.unity3d.com/Manual/index.html) Containing everything you could ever need, the documentation of OnCollisionEnter() Event is here (https://docs.unity3d.com/ScriptReference/Collider.OnCollisionEnter.html)
I will get back to you on the other question.
It seems, you can change your editor to Visual Studio and use it’s Intellisense, and learn information as you program on which methods are available for which classes and such.
You can do this by: going into Unity and going under edit/preferences and set devenv as the editor, precisely… this is the Visual Studio’s launcher, that you must path down to… atleast… that’s what i did.
It’s path is this, with the * representing a wildcard, meaning things before that are interchangeable.
PATH: *\Visual Studio 2017 Community\Common7\IDE\devenv.exe
OH, and one more thing… please be wary of where you post things.. You are in the challenges postal area.
But it should be fine, just be aware before you post next time…
I hope i have proved of some use.