Add documentation about blocks in restricted editing

[Witoso]

We need to add documentation about the blocks in restricted editing demos.

Currently, the restricted editing demos don't have sufficient documentation explaining how blocks work within the restricted editing feature.
This documentation should cover:

• Demo including a block
• How blocks are defined and used in restricted editing
• How to work with editable and non-editable blocks
• Examples and use cases for block-based restricted editing

This documentation will help users better understand and implement the restricted editing feature in their projects.