Documentation improvements: Aggregates

[alexeyfv]

Hello,

I made the following improvements to the Aggregate page:

1. Added a link to the Identity page. Seems like it was missing.
2. Briefly explained why it's important to use the SingleValueObjectConverter class with the Identity class.
3. Changed the code snippet in the "Using Events" section to make it more clear.
4. Added examples of how to modify aggregates using the IAggregateStore and the CQRS approach.

[CLAassistant]

All committers have signed the CLA.

[Copilot]

Copilot reviewed 1 out of 1 changed files in this pull request and generated 2 comments.

[rasmus]

Some very odd comments from copilot. Testing it out to see if it actually has any value.

[rasmus]

Thanks for the updates. It really means a lot!