Add toggle-thinkpad script

Toggles in-laptop keyboard/trackpad after plugging in USB ThinkPad
keyboard/TrackPoint.
Add setup for USB ThinkPad TrackPoint
Rename `start-synaptics` to `pointer`

Matches `keyboard` (more generic).
Add `k` = `keyboard` + `pointer`
Disentangle `git co` and `git cl`

Previously, `git co` (`gco`) conflated `checkout` and `clone`.

- Left `checkout` as `git co`
- Moved `clone` (with short repo names) to `git cl` (`gcl`)
Use `paredit` in Racket modes
Fix typo in `humanfy` (wrong case in var name)
Ignore `pre-commit` hook when running `git wip`
Default `toggle-thinkpad` to "disable"

If the keyboard is enabled, but the trackpad is disabled, I probably
want to disable the keyboard, not enable the trackpad.