Remove inconsistent references to "type" in NNAPI

"Type" in the NNAPI refers both to "OperandCode" and
"ANeuralNetworksOperandType" throughout the NNAPI documentation.

To make the documentation more consistent and less ambiguous,
this CL uses documentation links to the name itself instead of "type".

Bug: 72650109
Test: None, only documentation changes
Change-Id: I6718063da98a9c7ad10c4bb0452bca9a8986270b