Enhanced middleware documentation with advanced features

[amanluthra001]

Added comprehensive middleware examples including:

• Rate limiting middleware
• JWT authentication
• Security headers
• Request validation
• Logging and timeout middleware
• Best practices guide

[Umang01-hash]

@amanluthra001 You have copied and pasted your new content on top of already present documentation. The result is we have heading and documentation repeated. If you want to improve it please refactor the existing documentation with needed or missed things. We already have some of the things and hence they appeared re-written.

[amanluthra001]

@amanluthra001 You have copied and pasted your new content on top of already present documentation. The result is we have heading and documentation repeated. If you want to improve it please refactor the existing documentation with needed or missed things. We already have some of the things and hence they appeared re-written.

I have addressed the duplication issue you mentioned.
Changes made:

Removed all duplicate headings and content
Kept the original middleware documentation intact
Added new advanced examples (rate limiting, JWT auth, security headers, etc.) as enhancements to the existing content
Properly integrated new sections without replacing existing documentation

The documentation now flows from basic to advanced examples without any repetition. Please review the updated PR.
Thanks for your guidance!