Minor: Add Bacon to acknowledgments, invert a lint, update notes

docs/notes.md

@@ -20,3 +20,11 @@ See also:
     - <https://doc.rust-lang.org/std/collections/struct.BTreeMap.html#background>
     - `clippy::iter_over_hash_type`
 
+
+## Overall guidelines
+
+- Take refs, return owned
+- Avoid opacity
+    - Third-party macros
+    - Procedural macro attributes
+    - Returning opaque types, like `impl Trait`