Add `ToolbarButtons`

lib/src/widgets/toolbar/enum.dart

@@ -0,0 +1,30 @@
+enum ToolbarButtons {
+  undo,
+  redo,
+  fontFamily,
+  fontSize,
+  bold,
+  italic,
+  small,
+  underline,
+  strikeThrough,
+  inlineCode,
+  color,
+  backgroundColor,
+  clearFormat,
+  centerAlignment,
+  leftAlignment,
+  rightAlignment,
+  justifyAlignment,
+  direction,
+  headerStyle,
+  listNumbers,
+  listBullets,
+  listChecks,
+  codeBlock,
+  quote,
+  indentIncrease,
+  indentDecrease,
+  link,
+  search,
+}