Install psalm as dev, sync scripts updates

vendor/felixfbecker/language-server-protocol/src/SaveOptions.php

@@ -0,0 +1,15 @@
+<?php
+
+namespace LanguageServerProtocol;
+
+/**
+ * Options controlling what is sent to the server with save notifications.
+ */
+class SaveOptions
+{
+    /**
+     * The client is supposed to include the content on save.
+     * @var bool|null
+     */
+    public $includeText;
+}