Examples/guidance for more complex shell escaping

[milas]

Escaping shell commands is very tricky! Often in Starlark/Python, it means a combination of multiline (aka triple-quote ''') strings + raw strings (r"foo").

We've already got a few examples in the docs for shlex.quote: https://docs.tilt.dev/api.html#modules.shlex.quote

But we could probably stand to add a couple more for more complex cases with embedded quoting, for example.