Fix scope of @typedef references (#16718)

* Fix scope of @typedef references

* Remove unused variables

src/services/utilities.ts

@@ -275,6 +275,13 @@ namespace ts {
     }
 
     export function getContainerNode(node: Node): Declaration {
+        if (node.kind === SyntaxKind.JSDocTypedefTag) {
+            // This doesn't just apply to the node immediately under the comment, but to everything in its parent's scope.
+            // node.parent = the JSDoc comment, node.parent.parent = the node having the comment.
+            // Then we get parent again in the loop.
+            node = node.parent.parent;
+        }
+
         while (true) {
             node = node.parent;
             if (!node) {

tests/cases/fourslash/findAllRefsJsDocTypeDef_js.ts

@@ -0,0 +1,20 @@
+/// <reference path='fourslash.ts'/>
+
+// Tests that the scope of @typedef is not just the node immediately below it.
+
+// @allowJs: true
+
+// @Filename: /a.js
+/////** @typedef {number} [|{| "isWriteAccess": true, "isDefinition": true |}T|] */
+////
+/////**
+//// * @return {[|T|]}
+//// */
+////function f(obj) { return 0; }
+////
+/////**
+//// * @return {[|T|]}
+//// */
+////function f2(obj) { return 0; }
+
+verify.singleReferenceGroup("type T = number");