Replace cargo-cranky with workspace lints (#4413)

Replace `cargo-cranky` (which has served us well) with workspace lints

examples/custom_window_frame/src/main.rs

@@ -1,6 +1,7 @@
 //! Show a custom window frame instead of the default OS window chrome decorations.
 
 #![cfg_attr(not(debug_assertions), windows_subsystem = "windows")] // hide console window on Windows in release
+#![allow(rustdoc::missing_crate_level_docs)] // it's an example
 
 use eframe::egui::{self, ViewportCommand};