Add proc macros for Hint and edge (#63)

* Add proc-macro crate with two macros

* Let cargo recalculate the Cargo.lock

* Add tests and refactor some code to allow testing

also the impl for parse_hint_helper_attrs now preserves order
(which is essential for testing)

core/editor/src/hint.rs

@@ -0,0 +1,5 @@
+use std::collections::HashMap;
+
+pub trait Hint {
+	fn hints(&self) -> HashMap<String, String>;
+}