Syncronize the help strings in the C code with the documentation help strings

[DirectXMan12]

Currently the C code's doc strings don't even match the first line of the actual documentation.

They should either:

1. Just have the first line of the actual docs
2. Have the full docs

If the second choice is elected, we need to figure out the best way to read them from a file, perhaps as set of preprocessor macros generated at build time.