Start generating documentation for built-in types and functions

rust_compiler/libs/parser/src/lib.rs

@@ -1,3 +1,4 @@
+mod macros;
 #[cfg(test)]
 mod test;
 
@@ -14,6 +15,10 @@ use tokenizer::{
 };
 use tree_node::*;
 
+pub trait Documentation {
+    fn docs(&self) -> String;
+}
+
 #[macro_export]
 /// A macro to create a boxed value.
 macro_rules! boxed {