Add some notes to ir.rst
Add some notes to ir.rst

IntelLabs/numba,IntelLabs/numba,pitrou/numba,gdementen/numba,stonebig/numba,stuartarchibald/numba,stuartarchibald/numba,jriehl/numba,pitrou/numba,sklam/numba,numba/numba,jriehl/numba,seibert/numba,stuartarchibald/numba,stefanseefeld/numba,stefanseefeld/numba,sklam/numba,stonebig/numba,cpcloud/numba,pombredanne/numba,pitrou/numba,pombredanne/numba,cpcloud/numba,seibert/numba,numba/numba,numba/numba,gmarkall/numba,sklam/numba,jriehl/numba,gdementen/numba,numba/numba,pitrou/numba,stuartarchibald/numba,gmarkall/numba,stefanseefeld/numba,stonebig/numba,sklam/numba,pombredanne/numba,stefanseefeld/numba,pitrou/numba,ssarangi/numba,ssarangi/numba,gmarkall/numba,GaZ3ll3/numba,stonebig/numba,IntelLabs/numba,stuartarchibald/numba,ssarangi/numba,IntelLabs/numba,jriehl/numba,gdementen/numba,IntelLabs/numba,GaZ3ll3/numba,gdementen/numba,GaZ3ll3/numba,stefanseefeld/numba,gmarkall/numba,seibert/numba,ssarangi/numba,ssarangi/numba,gmarkall/numba,cpcloud/numba,cpcloud/numba,pombredanne/numba,numba/numba,seibert/numba,sklam/numba,jriehl/numba,stonebig/numba,pombredanne/numba,gdementen/numba,GaZ3ll3/numba,seibert/numba,GaZ3ll3/numba,cpcloud/numba