Update documentation noting the debugger_visualizer crate feature is an unstable feature.

Ridwan Abdilahi · Ridwan Abdilahi · commit 046464d8bccd · 2022-08-04T10:43:16.000-07:00
diff --git a/url/Cargo.toml b/url/Cargo.toml
@@ -35,6 +35,7 @@ serde = {version = "1.0", optional = true, features = ["derive"]}
 
 [features]
 default = ["idna"]
+# UNSTABLE FEATURES (requires Rust nightly)
 # Enable to use the #[debugger_visualizer] attribute.
 debugger_visualizer = []
 
