Update notebook.rst instructions using JupyterHub + Bokeh. (#8121)
Update notebook.rst instructions using JupyterHub + Bokeh. (#8121)

* Update notebook.rst instructions using JupyterHub + Bokeh.

* add blank line for code blocks

ericmjl/bokeh,timsnyder/bokeh,ericmjl/bokeh,timsnyder/bokeh,timsnyder/bokeh,mindriot101/bokeh,bokeh/bokeh,bokeh/bokeh,dennisobrien/bokeh,ericmjl/bokeh,jakirkham/bokeh,mindriot101/bokeh,ericmjl/bokeh,jakirkham/bokeh,dennisobrien/bokeh,jakirkham/bokeh,stonebig/bokeh,stonebig/bokeh,bokeh/bokeh,timsnyder/bokeh,bokeh/bokeh,timsnyder/bokeh,dennisobrien/bokeh,dennisobrien/bokeh,jakirkham/bokeh,mindriot101/bokeh,dennisobrien/bokeh,stonebig/bokeh,stonebig/bokeh,mindriot101/bokeh,bokeh/bokeh,jakirkham/bokeh,ericmjl/bokeh