feature request: task::Cancel command

[nickav]

In my editor I would like to make a keybinding to cancel the latest build, something like this:

// File: keymap.json
[
  {
    "bindings": {
      "f5": ["task::Spawn", { "task_name": "Build" }],
      "shift+f5": ["task::Cancel", { "task_name": "Build" }]
    }
  },
]

This is really helpful when making things that either hang or are expected to live for a long time (e.g. games/apps).