Docs for #2139.
Docs for #2139.

This adds documentation around the provision of routines only
accepting floating point types in the numba `np.linalg`
implementations.

Intended to close #2139.

seibert/numba,IntelLabs/numba,jriehl/numba,cpcloud/numba,seibert/numba,stonebig/numba,gmarkall/numba,cpcloud/numba,stonebig/numba,seibert/numba,seibert/numba,stonebig/numba,jriehl/numba,sklam/numba,stuartarchibald/numba,sklam/numba,jriehl/numba,stuartarchibald/numba,numba/numba,numba/numba,stuartarchibald/numba,jriehl/numba,IntelLabs/numba,IntelLabs/numba,gmarkall/numba,jriehl/numba,stonebig/numba,stonebig/numba,sklam/numba,cpcloud/numba,sklam/numba,stuartarchibald/numba,cpcloud/numba,numba/numba,gmarkall/numba,sklam/numba,gmarkall/numba,stuartarchibald/numba,numba/numba,IntelLabs/numba,seibert/numba,IntelLabs/numba,numba/numba,gmarkall/numba,cpcloud/numba