Fix links

Author: markshannon

peps/pep-0804.rst

@@ -116,7 +116,7 @@ stopped until the lock is released. If two threads attempt to acquire the stop-t
 in such a way that deadlock would occur, then an exception is raised.
 
 
-.. _super-threads
+.. _super-threads:
 
 SuperThread objects
 -------------------
@@ -530,7 +530,7 @@ If, instead, we expect an immutable object, we can just check that the object is
 
 The JIT compiler can remove redundant checks on the same object.
 
-.. _future-enhancements
+.. _future-enhancements:
 
 Possible future enhancements
 ============================