[v81d]

This PR adds the following fixes regarding user security and privacy:

• Commands were previously read directly as arguments, meaning anyone could see the full process directly via the ps command at the right moment. This can leak data if the inputted command contained secrets. Reading from stdin will prevent the command from appearing in the process list. (All shell hooks now pipe the to-be-checked command directly instead of passing it as an argument.)
• Implemented a warning when adding regrets to make sure the user did not submit a command containing secrets.

[v81d]

Possible (future) improvements (v0.4.0?):

• Perhaps make the regret-adding process interactive and (somehow) erase each prompt after submission to prevent sensitive info from lingering in the terminal session.
• Add regex or glob support so its way more flexible.