DOC: Add example to histogram2d docstring
DOC: Add example to histogram2d docstring

endolith/numpy,endolith/numpy,jakirkham/numpy,endolith/numpy,simongibbons/numpy,numpy/numpy,mhvk/numpy,mhvk/numpy,jakirkham/numpy,mattip/numpy,charris/numpy,jakirkham/numpy,mattip/numpy,mhvk/numpy,seberg/numpy,mhvk/numpy,simongibbons/numpy,numpy/numpy,anntzer/numpy,mhvk/numpy,rgommers/numpy,jakirkham/numpy,anntzer/numpy,anntzer/numpy,charris/numpy,simongibbons/numpy,simongibbons/numpy,charris/numpy,mattip/numpy,seberg/numpy,pdebuyl/numpy,charris/numpy,rgommers/numpy,pdebuyl/numpy,jakirkham/numpy,pdebuyl/numpy,seberg/numpy,rgommers/numpy,mattip/numpy,numpy/numpy,endolith/numpy,rgommers/numpy,anntzer/numpy,pdebuyl/numpy,seberg/numpy,simongibbons/numpy,numpy/numpy