Rust: extract isRef for SelfParam

rust/schema/annotations.py

@@ -1546,12 +1546,18 @@ class _:
 
 
 @annotate(SelfParam, replace_bases={AstNode: ParamBase}, cfg = True)
+@rust.doc_test_signature(None)
 class _:
     """
     A `self` parameter. For example `self` in:
     ```rust
-    fn push(&mut self, value: T) {
-      // ...
+    struct X;
+    impl X {
+      fn one(&self) {}
+      fn two(&mut self) {}
+      fn three(self) {}
+      fn four(mut self) {}
+      fn five<'a>(&'a self) {}
     }
     ```
     """