Document single-line and multi-line commenting for Bend users

[kings177]

We need to create user documentation for the commenting feature.

Tasks:

Create a section in the documentation that explains how to use comments in bend. This should cover both single-line and multi-line comments.

Key points to include:

1. Single-line comments:

• Syntax: Use # at the beginning of a line or after code
• Example Usage

2. Multi-line comments:

• Syntax: Use #{ to start and #} to end a multi-line comment
• Example usage
• Mention that they can span multiple lines