jupyter: Add link in about to Jason Grout's comment on jupyter backgrund output capture.
jupyter: Add link in about to Jason Grout's comment on jupyter backgrund output capture.

tscholl2/smc,tscholl2/smc,DrXyzzy/smc,DrXyzzy/smc,sagemathinc/smc,DrXyzzy/smc,tscholl2/smc,sagemathinc/smc,tscholl2/smc,DrXyzzy/smc,sagemathinc/smc,tscholl2/smc,sagemathinc/smc