Overriding getter with member variable causes docs to get lost

[tvolkert]

Consider the following:

library foo;

/// Base class docs
class Base {
  /// Great, thorough documentation
  bool get foo => true;
}

/// Subclass docs
class Sub extends Base {
  @override
  final bool foo = false;
}

When I look up the dartdocs for Sub.foo, I expect to see "Great, thorough documentation". Yet there are no docs for Sub.foo.

[tvolkert]

/cc @jcollins-g

[jcollins-g]

This is another case that was fixed in as part of cleanups for #1765 and will be fixed when this lands. #1781 adds a specific test for this case.