Fork channel

Create a new channel as a copy of main.

Rename channel

Rename main to:

Delete channel

Delete main? This cannot be undone.

empty-MF.mir
# RUN: llc -mtriple aarch64-- -run-pass mir-canonicalizer %s -o - | FileCheck %s
# CHECK: ...
# CHECK-NEXT: ---
# CHECK-NEXT: name:            foo
# CHECK: body:             |
# CHECK-EMPTY:
# CHECK-NEXT: ...
---
name: foo
body:             |
...