Parse description from node doc comments (#2089)

* Parse description from node doc comments

* Add node description tooltips

* Code review

---------

Co-authored-by: Adam G <adamgerhant@gmail.com>
Co-authored-by: Keavon Chambers <keavon@keavon.com>

node-graph/gcore/src/registry.rs

@@ -34,6 +34,7 @@ pub struct NodeMetadata {
 	pub display_name: &'static str,
 	pub category: Option<&'static str>,
 	pub fields: Vec<FieldMetadata>,
+	pub description: &'static str,
 }
 
 #[derive(Clone, Debug)]

node-graph/gcore/src/vector/vector_data/modification.rs

@@ -500,6 +500,7 @@ fn modify_existing() {
 	);
 }
 
+// Do we want to enforce that all serialized/deserialized hashmaps are a vec of tuples?
 // TODO: Eventually remove this (probably starting late 2024)
 use serde::de::{SeqAccess, Visitor};
 use serde::ser::SerializeSeq;