C++ Transition Guide for 4.22

[NilsonLima]

@cmmmorgan

For anybody that is looking to upgrade macros such as BEGIN_UNIFORM_BUFFER_STRUCT to do with shader parameters, see this commit https://github.com/EpicGames/UnrealEngine/commit/c72b7a33d8e1dba50863522615ff2b3d5a197e90

Thanks for the heads up. This makes the understanding of the changes on several macros a lot easier. Cheers!