Add guarantees about the naming of requests and events to the protocol

This merge request updates the protocol documentation to explicitly specify that all requests and events must have unique names within the same interface. While this was implicitly followed in practice by nearly all existing protocols, it was not formally stated in the documentation.

In reviewing the 109 protocols I am currently generating with my library, I found that nearly all adhered to this naming convention without issue. Specifically, I encountered only one protocol that did not meet this requirement, and upon further investigation, the authors of that protocol confirmed that the naming conflict was unintentional and introduced in error. More information on this specific case can be found in this issue.

Signed-off-by: Federico Maria Morrone contact@morrone.dev