chore(ckeditor5/plugins): integrate indent block shortcut

packages/ckeditor5/src/plugins/indent_block_shortcut.ts

@@ -0,0 +1,44 @@
+/**
+ * https://github.com/zadam/trilium/issues/978
+ */
+
+import { DocumentFragment, Element, Plugin, Position } from "ckeditor5";
+
+export default class IndentBlockShortcutPlugin extends Plugin {
+
+    init() {
+        this.editor.keystrokes.set( 'Tab', ( _, cancel ) => {
+            const command = this.editor.commands.get( 'indentBlock' );
+
+            if (command && command.isEnabled && !this.isInTable() ) {
+                command.execute();
+                cancel();
+            }
+        } );
+
+        this.editor.keystrokes.set( 'Shift+Tab', ( _, cancel ) => {
+            const command = this.editor.commands.get( 'outdentBlock' );
+
+            if (command && command.isEnabled && !this.isInTable() ) {
+                command.execute();
+                cancel();
+            }
+        } );
+    }
+
+    // in table TAB should switch cells
+    isInTable() {
+        let el: Position | Element | DocumentFragment | null = this.editor.model.document.selection.getFirstPosition();
+
+        while (el) {
+            if ("name" in el && el.name === 'tableCell') {
+                return true;
+            }
+
+            el = "parent" in el ? el.parent : null;
+        }
+
+        return false;
+    }
+
+}