Stale issues with better closing message

[poyea]

Perhaps we have to change the "Stale pull request message" to something like "Please reopen this once you commit the changes requested / make improvements on the code".

[cclauss]

Please consider making a pull request.
https://github.com/TheAlgorithms/Python/blob/master/.github/stale.yml#L17