Fix memory caching documentation in Lesson 5 - correct DELETE instruction to MODIFY

[Copilot]

The documentation in Lesson 5 incorrectly instructed students to DELETE the entire AddOutputCache configuration block when integrating Redis output caching:

// Add default output caching
services.AddOutputCache(options =>
{
    options.AddBasePolicy(builder => builder.Cache());
});

However, examining the /complete solution reveals this code should be modified, not deleted. The complete solution retains the AddOutputCache configuration but adds cache tagging:

// Add default output caching
services.AddOutputCache(options =>
{
    options.AddBasePolicy(builder => builder.Tag("AllCache")
                            .Cache());
});

This change:

• Corrects the documentation to instruct students to modify the existing code rather than delete it
• Preserves output caching functionality that works alongside Redis integration
• Enables cache invalidation through the "AllCache" tag used elsewhere in the complete solution
• Aligns with the actual implementation shown in the complete solution

The Redis output cache integration (builder.AddRedisOutputCache("cache")) works by redirecting the existing output cache configuration to use Redis instead of in-memory storage, making the preservation of this configuration essential.

Fixes #183.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• aka.ms
  • Triggering command: curl -I -sSL --retry 5 --retry-delay 2 --connect-timeout 15 REDACTED (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

---

💬 Share your feedback on Copilot coding agent for the chance to win a $200 gift card! Click here to start the survey.

[Copilot]

Pull Request Overview

This PR corrects documentation in Lesson 5 that incorrectly instructed students to delete the AddOutputCache configuration when integrating Redis output caching. The fix changes the instruction from deletion to modification, aligning the documentation with the actual implementation in the complete solution.

Key Changes

• Corrects lesson instructions to modify rather than delete the AddOutputCache configuration
• Adds cache tagging functionality (Tag("AllCache")) to enable cache invalidation
• Updates explanatory text to clarify how Redis integration works with existing output cache policies