Update dev tricks

These are the cool project-specific hacks I use with ZSH and NeoVim. I believe they add value even to people who don't use ZSH or NeoVim, as it may encourage them to set similar things up for their respective shells and editors and contribute those to the project.

Labeled WIP because it seems rust-analyzer is not playing ball by default, causing an insane amount of compilation for no good reason. It must be configured to be nice, and documented, or replaced.