Updated deploy.rst for better clarity

[najasnake12]

I changed deploy.rst for better clarity specifically this part:
Before:
$ python -c 'import secrets; print(secrets.token_hex())'

'192b9bdd22ab9ed4d12e236c78afcb9a393ec15f71bbf5dc987d54727823bcbf'

After:
$ python -c 'import secrets; print(secrets.token_hex())'

Example secret key:
'192b9bdd22ab9ed4d12e236c78afcb9a393ec15f71bbf5dc987d54727823bcbf'

[ThiefMaster]

I wonder whether we shouldn't simply blacklist that particular not-so-secret key, since I guess there's always a chance that people copy it instead of generating their own, even with that line message...

Also I don't think that adding this message is a good idea - this code block shows a shell command and its output, and that message you added is not part of the output.