Add components to implementation record

[andysellick]

What

In the GA4 implementation record, where an event occurs on a component, document and link to the component guide page for that component. This is done per-event, as some event groupings apply to more than one component.

Why

Part of improving the implementation record for users.

Visual changes

[AshGDS]

Nice 👍 How does this work when the event applies to more than one component? E.g. the callout tracking would have worked on both the warning text component, and the govspeak component before I removed it from the govspeak component due to it affecting external links.

[andysellick]

@AshGDS yeah I thought about that. I think if we encounter that in future we can either extend this functionality (so the component is a comma separated list or something) or separate the event out into two events.

There are some other slightly complicated things that I just decided were too nuanced for the purposes of this documentation. For example when we have attachments rendered inside govspeak - explaining how that all fits together for a non-technical audience seemed too much, so I just pointed it at the attachment component page instead.