[FR] Add linking/tagging/text tokenization example

[Adel0n]

Description

Would be great to have simple examples of using Appflowy Editor to build linking/tagging or any other text tokenization, like date, people mentioned, etc. Something like SuperEditor provides:

• https://github.com/superlistapp/super_editor/blob/main/super_editor/example/lib/demos/in_the_lab/feature_stable_tags.dart
• https://github.com/superlistapp/super_editor/blob/main/super_editor/example/lib/demos/in_the_lab/feature_pattern_tags.dart
• https://github.com/superlistapp/super_editor/blob/main/super_editor/example/lib/demos/in_the_lab/feature_action_tags.dart

While it's definitely possible to examine Appflowy app code for implementing referencing, it will be much easier for new users to look at a simple example first.

Impact

New users, who want to adopt Appflowy Editor and see more use cases of possible features.

Additional Context

No response