Ref T5378. Although some dicussion there talks about separating "self-uri" matching and non-self-URI matching into two phases, the URI matching code has enough weird magic that it felt cleaner to put them in one phase with an extension point.
Match URIs into structured data, then allow extensions to specialize the rendering behavior. This matches three flavors of URI:
- "uri" can be specialized.
- "<uri>" is a "literal" URI and can NOT be specialized. This already exists/works.
- "{uri}" is an "embedded" URI and can ONLY be specialized (the default rendering is just the plain text).
On its own, this change doesn't affect any rendering behavior.
