Via:

  - https://jvns.ca/blog/2024/02/16/popular-git-config-options/
  - https://ductile.systems/zdiff3/

Uses git-diff-index.

Also adds `git ec` alias so maybe I remember to use this.

Use SSH instead of HTTPS endpoint.

...for Gerrit remotes, of which there are a lot in my life these days.

Also includes a basic README for the cheatsheets directory.

Amends last commit by tacking on current changes.

See:  https://p1k3.com/2017/3/11/

Uses `git rev-parse --show-toplevel`

...seems like a more lightweight way of providing various settings to
Gtk apps (and maybe other stuff? I'm not sure).

Various other font tweaks and such in this commit.

(wthr has its own repo)

p & pul for pull, because i'm always doing this
s for status because why type two chars?
go for checkout because i'm always typoing it as this and why not
l for log