jupyter: make normal tab work, when nothing to complete
jupyter: make normal tab work, when nothing to complete

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