docs: add delta range example for collectible achievements

[G3mha]

The /docs/developer-docs/real-examples/using-add-source-and-deltas-for-collectibles-and-similar-achievements.md file mentions delta ranges but needs a concrete example.

Add:

• Code example showing delta range implementation
• Screenshot demonstrating the concept
• Explanation of why/when to use ranges vs single values
• Common edge cases to watch for

Current reference:

"...could be changed to <= 0x09 and the total for the second group could be >= 0x05"