[ty] Remove duplicate global lint registry (#20053)

## Summary

Looks like an oversight at some point that led to two identical globals,
the one in `ty_project` just calls `ty_python_semantic::register_lints`.

crates/ruff_dev/src/generate_ty_rules.rs

@@ -52,7 +52,7 @@ pub(crate) fn main(args: &Args) -> Result<()> {
 }
 
 fn generate_markdown() -> String {
-    let registry = &*ty_project::DEFAULT_LINT_REGISTRY;
+    let registry = ty_python_semantic::default_lint_registry();
 
     let mut output = String::new();