Constructor colouring on DartDocs is not working

[FMorschel]

Originally posted in #59724:

From #59910 (comment):

Dartdoc prefers the A.foo instance member. To specifically refer to the constructor, you can use A.foo(). We should document this behavior here: https://dart.dev/tools/doc-comments/references

So for this code, you can differentiate between them:

/// A class with [A.foo] and [A.foo()]
class A {
  int foo = 0;
  A.foo();
}

But there is no colouring for A.foo() (currently being suggested correctly). [...]

Also noticed the . has no colouring here. Not a big deal but it is a bit weird.

CC @DanTup

[DanTup]

I think this is probably the same as #47553. In the code above, there are no regions parsed for the one with the parens, so we don't provide navigation (or colouring) for it. That issue was specifically about functions, but I just tested with constructors and it seems to be the same.

(FYI @srawlins .. should we close this one as a dupe of that?)

[FMorschel]

I missed it. Thanks! I'll post whatever I feel is missing there just so we have it all in one place.