Make .meta.json changes cause scripts to be updated

src/snapshots/serve_session__script_with_meta.snap

@@ -0,0 +1,30 @@
+---
+source: src/serve_session.rs
+expression: "view_tree(&session.tree(), &mut rm)"
+---
+id: id-1
+name: root
+class_name: Folder
+properties: {}
+metadata:
+  ignore_unknown_instances: false
+  instigating_source:
+    Path: /root
+  relevant_paths:
+    - /root
+children:
+  - id: id-2
+    name: test
+    class_name: ModuleScript
+    properties:
+      Source:
+        Type: String
+        Value: This is a test.
+    metadata:
+      ignore_unknown_instances: true
+      instigating_source:
+        Path: /root/test.lua
+      relevant_paths:
+        - /root/test.lua
+        - /root/test.meta.json
+    children: []