Feature request: data backup

[hawkish136]

I hope to add a buffer backup function. During one use, I triggered two full selections, which resulted in all historical records being overwritten.

[heyman]

It should be fairly simple to set up automatic backup of the buffer file manually, so I'm not sure it's a feature that Heynote need to have.

If you accidentally select the whole buffer and overwrite it, undo should work to get it back (though if you close the program the history will be lost).