0f1a01807c
While looking at https://github.com/llvm/llvm-project/issues/49528 I found that, happily, aliases can now be tab completed. However, if there is a built-in match that will always be taken. Which is a bit surprising, though logical if we don't want people really messing up their commands I guess. Meaning "b" tab completes to our built-in breakpoint alias, before it looks at any of the aliases. "bf" doesn't match "b", so it looks through the aliases. I didn't find any tests for this in the obvious places, so this adds some.