Feature request: allow for manual history log too

Hi, I find Simple History very useful. Thanks so much for creating and maintaining it!

It would be wonderful if we could also enter manual entries to the log.

For example today I upgraded the Php version for the websites directory, it would be useful to record that change to help debug any issues that might arise

At the moment I keep an additional document for logging manual changes but it would be much easier to keep it all within Simple History. Anyway just an idea