chore: checkpoint before Python removal

vendor/pin-project/examples/project_replace.rs

@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+// See ./struct-default-expanded.rs for generated code.
+
+#![allow(dead_code)]
+
+use pin_project::pin_project;
+
+#[pin_project(project_replace)]
+struct Struct<T, U> {
+    #[pin]
+    pinned: T,
+    unpinned: U,
+}
+
+fn main() {}