Change wxSound ctor from in-memory data to use size_t/void *.

Change wxSound ctor from in-memory data to use size_t/void *.

This constructor previously used int and, especially annoyingly, wxByte* for
the data. Use standard void* for untyped binary data instead.

Also document this ctor as it seems to be implemented in all ports.

Closes #13451.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@69178 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775