webapp/chat: pre-tags for code in chat should inherit font size and the usual padding
webapp/chat: pre-tags for code in chat should inherit font size and the usual padding

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