Fix ambiguous language in the supported features docs
Fix ambiguous language in the supported features docs

Fix ambiguous language in the supported features. 
Add sentence to explicitly state that the features below are supported.
jriehl/numba,sklam/numba,cpcloud/numba,seibert/numba,stonebig/numba,stuartarchibald/numba,IntelLabs/numba,jriehl/numba,numba/numba,jriehl/numba,IntelLabs/numba,numba/numba,stefanseefeld/numba,IntelLabs/numba,gmarkall/numba,cpcloud/numba,stefanseefeld/numba,stonebig/numba,stefanseefeld/numba,cpcloud/numba,numba/numba,stefanseefeld/numba,stonebig/numba,stonebig/numba,jriehl/numba,gmarkall/numba,sklam/numba,seibert/numba,numba/numba,seibert/numba,sklam/numba,stuartarchibald/numba,cpcloud/numba,gmarkall/numba,stonebig/numba,stuartarchibald/numba,IntelLabs/numba,stefanseefeld/numba,stuartarchibald/numba,gmarkall/numba,IntelLabs/numba,sklam/numba,stuartarchibald/numba,seibert/numba,sklam/numba,jriehl/numba,seibert/numba,numba/numba,cpcloud/numba,gmarkall/numba