Revert D31447613: Create separate documentation pages for quantization observers and fake_quants
Test Plan: revert-hammer
Differential Revision:
D31447613 (https://github.com/pytorch/pytorch/commit/f0fa3d1110fdd085b040ef82c8a547b205b98e38)
Original commit changeset: 63b4cf518bad
fbshipit-source-id: 67de592d1e12a5149cdb22b0725caad063f94476
