Remove XXX comments from changes.rst

doc/changes.rst

@@ -190,8 +190,7 @@ C APIs (for vmod and utility authors)
 -------------------------------------
 
 * We have now defined three API Stability levels: ``VRT``,
-  ``PACKAGE``, ``SOURCE``. XXX: someone should write up an rst when
-  we've settled this.
+  ``PACKAGE``, ``SOURCE``.
 
 * New API namespace rules, see `phk_api_spaces_`
 
@@ -200,8 +199,6 @@ C APIs (for vmod and utility authors)
   * some headers require specific include ordering
   * only ``cache.h`` _or_ ``vrt.h`` can be included
 
-  XXX: More details?
-
 * Signatures of functions in the VLU API for bytestream into text
   serialization have been changed
 
@@ -244,8 +241,6 @@ C APIs (for vmod and utility authors)
   have the ``(struct director).admin_health`` initialized to
   ``VDI_AH_*`` (usually ``VDI_AH_HEALTHY``).
 
-  XXX improve / more details
-
 Other changes relevant for VMODs
 --------------------------------