Complete the drilldown from diagrams to hook doc pages

[sambarza]

In the drawio diagrams under "Core Process Diagrams" is possible to click on hooks to navigate from the diagram to the hook doc page.
Example, try to click on the hook before_cat_reads_message in the Call of Cat diagram (you can access the diagram Call of Cat from the diagram Chatting with the Cat step 2. call the Cat).

We should complete the navigation links, from the diagrams to the doc, for all hooks.