Install psalm as dev, sync scripts updates

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

@@ -0,0 +1,25 @@
+<?php
+
+namespace LanguageServerProtocol;
+
+/**
+ * Defines how the host (editor) should sync document changes to the language server.
+ */
+abstract class TextDocumentSyncKind
+{
+    /**
+     * Documents should not be synced at all.
+     */
+    const NONE = 0;
+
+    /**
+     * Documents are synced by always sending the full content of the document.
+     */
+    const FULL = 1;
+
+    /**
+     * Documents are synced by sending the full content on open. After that only
+     * incremental updates to the document are sent.
+     */
+    const INCREMENTAL = 2;
+}