Add an example on how to multi-wrap functions

[lquenti]

First of all: Very cool! Found you cited in a paper about data provenance and never even realized that LD_PRELOAD has those limitations to begin with. Speaking of, your docs say

Gotcha’s API allows tool wrapping decisions to be made at runtime, and it handles cases of multiple tools wrapping the same function.

While the tee example is fun, could you create a small poc on how multi wrapping, and especially handling the precedence problem, would work?