Add documentation around source package consumption. (#34688)
Add documentation around source package consumption. (#34688)

* Add documentation around source package consumption.

* Fix typos and formatting.

* Add a sample csproj that users can reference.

ericstj/corefx,ViktorHofer/corefx,wtgodbe/corefx,ericstj/corefx,ptoonen/corefx,wtgodbe/corefx,ptoonen/corefx,ptoonen/corefx,shimingsg/corefx,ViktorHofer/corefx,ViktorHofer/corefx,wtgodbe/corefx,ViktorHofer/corefx,wtgodbe/corefx,shimingsg/corefx,ViktorHofer/corefx,ptoonen/corefx,ViktorHofer/corefx,ericstj/corefx,ptoonen/corefx,shimingsg/corefx,ericstj/corefx,shimingsg/corefx,shimingsg/corefx,shimingsg/corefx,ViktorHofer/corefx,BrennanConroy/corefx,wtgodbe/corefx,ericstj/corefx,BrennanConroy/corefx,ericstj/corefx,wtgodbe/corefx,shimingsg/corefx,ericstj/corefx,ptoonen/corefx,BrennanConroy/corefx,wtgodbe/corefx,ptoonen/corefx