Fork channel

Create a new channel as a copy of main.

Rename channel

Rename main to:

Delete channel

Delete main? This cannot be undone.

fixups-invalid.s
# RUN: not llvm-mc -filetype=obj %s -triple=riscv32 -o /dev/null 2>&1 \
# RUN:     | FileCheck %s
# RUN: not llvm-mc -filetype=obj %s -triple=riscv64 -o /dev/null 2>&1 \
# RUN:     | FileCheck %s

.byte foo   # CHECK: [[@LINE]]:7: error: 1-byte data relocations not supported
.2byte foo  # CHECK: [[@LINE]]:8: error: 2-byte data relocations not supported