Fix documentaiton formatting errors.

 i) Fix documentation formatting errors converting a
     major part of the documentation into a link.
ii) Remove the DEVICE_ORIENTATION type documentation. Its
         a hidden sensor type, and links to the sensor fail.

Test: Compile build, generate docs, visually verify change.
Change-Id: I2659d18e35b60f5939ba18c6b3d752a990621447