Sometimes we populate the commit message panel with a pre-created commit
message. The two cases where this happens is:
- you type `w` to commit, in which case we put the skipHookPrefix in the subject
- you have a commitPrefix pattern, in which case we match it against the branch
name and populate the subject with the replacement string if it matches
In either case, if you have a preserved commit message, we use that.
Now, when you use either of these and then cancel, we preserve that initial,
unchanged message and reuse it the next time you commit. This has two problems:
it strips spaces, which is a problem for the commitPrefix patterns, which often
end with a space. And also, when you change your config to experiment with
commitPrefix patterns, the change seemingly doesn't take effect, which can be
very confusing.
To fix both of these problems, only preserve the commit message when it is not
identical to the initial message.
3a30211099