Previously the entire status was colored in a single color, so the API made
sense. This is going to change in the next commit, so now we must include the
color in the string returned from BranchStatus(), which means that callers who
need to do hit detection or measure the length need to decolorize it.
While we're at it, switch the order of ↑3↓7 to ↓7↑3. For some reason that I
can't really explain I find it more logical this way. The software out there is
pretty undecided about it, it seems: VS Code puts ↓7 first, and so does the
shell prompt that comes with git; git status and git branch -v put "ahead" first
though. Shrug.
Changing globals in the init() function of a test file is a bad idea, as it
affects all other tests that run after it. Do it explicitly in each test
function that needs it, and take care of restoring the previous value
afterwards.
