Crate completion_derive

How to use value hints and generate shell completions.

Usage with zsh:

cargo run --example value_hints_derive -- --generate=zsh > /usr/local/share/zsh/site-functions/_value_hints_derive
compinit
./target/debug/examples/value_hints_derive --<TAB>

fish:

cargo run --example value_hints_derive -- --generate=fish > value_hints_derive.fish
. ./value_hints_derive.fish
./target/debug/examples/value_hints_derive --<TAB>