docs: update `query` refresh/update sections

Describe the problem

Unify expressions

Same goal, different terms. Maybe they can be unified to Updating Queries?

• Query section: Refreshing Queries - it only mentions refresh
• Form section: Single-flight mutations - basically an option to do a manual refresh
• Command section: Updating Queries - refresh and customizing enhance in one

Provide reference

The command section shows both

• refresh()
• client-driven single-flight mutations from the customizing enhance section

but the latter is not linked to its source for easy reference.

It just says 'as before', so I had to search for the override keyword in the page.

...or when we call it:

await addLike(item.id).updates(getLikes(item.id));

As before, we can use withOverride for optimistic updates:

await addLike(item.id).updates(
  getLikes(item.id).withOverride((n) => n + 1)
);

Describe the proposed solution

Alongside the above edits,

• Don't assume that a reader read the docs in order
• Separate each remote functions into independent pages
• Or at least show the parent section name

I cannot know that I am in a command section in a narrow viewport. The situation is not much different in a wider viewport, since I have to look at the right sidebar to monitor which section I am in.

Alternatives considered

No response

Importance

nice to have

Additional Information

No response

Start with the SvelteKit remote-functions documentation, especially the Query, Form, and Command sections and the refresh, updates, withOverride, and enhance references. Compare their terminology and links, then make the sections understandable without prior reading; done means the related source is linked and the parent section remains clear in narrow view.