Add test for wrap_pyfunction!() deduction.

Author: m-ou-se

tests/test_wrap_pyfunction_deduction.rs

@@ -0,0 +1,13 @@
+use pyo3::{prelude::*, types::PyCFunction, wrap_pyfunction};
+
+#[pyfunction]
+fn f() {}
+
+pub fn add_wrapped(wrapper: &impl Fn(Python) -> PyResult<&PyCFunction>) {
+    let _ = wrapper;
+}
+
+#[test]
+fn wrap_pyfunction_deduction() {
+    add_wrapped(wrap_pyfunction!(f));
+}