Links to headings look different from links to document

Copy a link to a heading, paste it into a document, and the mention renders as the document title alone. Two links pointing at different sections of the same document are visually identical, and a link to a heading in the document you are currently reading reads as a link to the document you are already in, so same-document section references are not usable at all. The anchor is already on the mention as anchorId since #12900, and the hover preview already shows the target section since #12857. Only the label never says where the link goes. | Link | Today | Proposed | | --- | --- | --- | | Heading in another document | Product Roadmap | Product Roadmap > Q3 goals | | Heading in the document being read | Product Roadmap | Q3 goals, with a icon | | Heading that no longer exists | Product Roadmap | Product Roadmap | The heading title would be stored on the mention when the link is pasted and resolved from the target document whenever its data is loaded, which is the same …