How to get the entire title when referencing headings?

Questions
1

For example, here is a code that references a title:

#set heading(numbering: "1.")

== Colours <sub:colours>

@sub:colours is a title

Instead of referencing as Section 0.1 is a title can I get something like - Colours is a title?

2

Hello!
I have changed your question to “How to get the entire title when referencing headings?”, if that’s wrong, please correct it!

The syntax @label is called a reference. See ref for more details, and in particular, you can read the section on Customization.

Inspecting the content of it inside the conditional statement, gives you

ref(
    target: <sub:colours>,
    supplement: auto, 
    form: "normal",
    citation: cite(key: <sub:colours>, supplement: none),
    element: heading(
        level: 2,
        depth: 2,
        offset: 0,
        numbering: "1.",
        supplement: [Section],
        outlined: true,
        bookmarked: auto,
        hanging-indent: auto,
        body: [Colours],
    ),
)

where you can see that the heading is in fact the element of ref (it). Accessing the title of the heading is as simple as writing it.element.body.

#set heading(numbering: "1.")
#show ref: it => {
  let el = it.element
  if el != none and el.func() == heading {
    link(el.location(), el.body)
  }
}
== Colours <sub:colours>
@sub:colours is a title