add note about shift+enter to side chat
add note about shift+enter to side chat

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