fix: sync the restored file and enable Find Usages when the LSP starts late

At app start a session-restored file is opened before the language server
finishes starting, so the per-file setup it normally gets on a file switch never
ran - jump-to-definition did nothing and "Find Usages" stayed disabled until the
user switched files once.

- DocumentSync.openSupportedDocuments now also didOpens the active editor's
  document (it may not yet be in getAllOpenDocuments() at server-start time), so
  the file the user is looking at is synced immediately.
- FindReferencesManager refreshes the command's enabled state when a provider
  registers (the state is otherwise only computed on file switch), so a
  late-registering LSP references provider lights up "Find Usages" right away.

Author: abose

src/features/FindReferencesManager.js

@@ -36,11 +36,22 @@ define(function (require, exports, module) {
         Strings                     = require("strings");
 
     var _providerRegistrationHandler = new ProviderRegistrationHandler(),
-        registerFindReferencesProvider = _providerRegistrationHandler.registerProvider.bind(
-            _providerRegistrationHandler
-        ),
         removeFindReferencesProvider = _providerRegistrationHandler.removeProvider.bind(_providerRegistrationHandler);
 
+    /**
+     * Register a find-references provider. The command's enabled state is normally computed on file
+     * switch; a provider can register *after* the active file is already open (e.g. an LSP server
+     * that starts asynchronously at app launch), so re-evaluate the menu state here too - otherwise
+     * "Find All References" stays disabled until the user switches files.
+     * @param {Object} providerInfo
+     * @param {Array<string>} languageIds
+     * @param {?number} priority
+     */
+    function registerFindReferencesProvider(providerInfo, languageIds, priority) {
+        _providerRegistrationHandler.registerProvider(providerInfo, languageIds, priority);
+        setMenuItemStateForLanguage();
+    }
+
     var searchModel = new SearchModel(),
         _resultsView;
 

src/languageTools/DocumentSync.js

@@ -191,7 +191,17 @@ define(function (require, exports, module) {
      * @param {Object} client - a LanguageClient
      */
     function openSupportedDocuments(client) {
-        DocumentManager.getAllOpenDocuments().forEach(function (doc) {
+        const docs = DocumentManager.getAllOpenDocuments().slice();
+        // Belt-and-suspenders: the file the user is actually looking at - e.g. a session-restored
+        // document at app start - may not yet appear in getAllOpenDocuments() at the moment the
+        // server finishes starting. Include the active editor's document explicitly so it is synced
+        // immediately, instead of only after the next file switch (which is what triggered the
+        // activeEditorChange safety net before).
+        const activeEditor = EditorManager.getActiveEditor();
+        if (activeEditor && activeEditor.document && docs.indexOf(activeEditor.document) === -1) {
+            docs.push(activeEditor.document);
+        }
+        docs.forEach(function (doc) {
             if (_isSupported(client, doc)) {
                 // Always (re)send didOpen with the current content. This is called right after a
                 // server (re)start, so any prior tracking is stale and must not be trusted - e.g.