Fixes several notable mistakes and missing information
regarding the API documentation (*.rst).
This will allow API stub generators like bpystubgen or
fake-bpy-module to produce more accurate result.
Differential Revision: https://developer.blender.org/D12639
Instead of creating different python wrappers for the same GPU object,
return the same `PyObject` created earlier.
This also allows for more secure access to existing GPU objects.
Reviewed By: brecht
Differential Revision: https://developer.blender.org/D11044