Add convenience repl_channel function.
Add convenience repl_channel function.

reddec/pika,vrtsystems/pika,hugoxia/pika,skftn/pika,benjamin9999/pika,fkarb/pika-python3,pika/pika,shinji-s/pika,Tarsbot/pika,Zephor5/pika,vitaly-krugl/pika,zixiliuyue/pika,jstnlef/pika,renshawbay/pika-python3,knowsis/pika