refactor: Rename runtime/rt to runtime/js (#8806)

runtime/js/40_diagnostics.js

@@ -0,0 +1,23 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
+// Diagnostic provides an abstraction for advice/errors received from a
+// compiler, which is strongly influenced by the format of TypeScript
+// diagnostics.
+
+((window) => {
+  const DiagnosticCategory = {
+    0: "Warning",
+    1: "Error",
+    2: "Suggestion",
+    3: "Message",
+
+    Warning: 0,
+    Error: 1,
+    Suggestion: 2,
+    Message: 3,
+  };
+
+  window.__bootstrap.diagnostics = {
+    DiagnosticCategory,
+  };
+})(this);