feature: add F9 as an alternative process kill key

[ClementTsang]

Description

A description of the change and what it does. If relevant (such as any change that modifies the UI), please provide screenshots of the change:

Adds F9 as an alternative kill shortcut to dd.

Testing

If relevant, please state how this was tested. All changes must be tested to work:

Furthermore, mark which platforms this change was tested on. All platforms directly affected by the change must be tested

• Windows
• macOS
• Linux

Checklist

If relevant, ensure the following have been met:

• Areas your change affects have been linted using rustfmt (cargo fmt)
• The change has been tested and doesn't appear to cause any unintended breakage
• Documentation has been added/updated if needed (README.md, help menu, etc.)
• The pull request passes the provided CI pipeline
• There are no merge conflicts