message: Allow compatibility notes in class, property and module doc-strings
diff: @@ -117,7 +117,8 @@ def _build_class_page(page_info):
  parts.append(page_info.guides)
  parts.append(page_info.doc.docstring)
  parts.append(_build_function_details(page_info.doc.function_details))
  - assert not page_info.doc.compatibility
  + parts.append(_build_compatibility(page_info.doc.compatibility))
  +
  parts.append('\n\n')
  if page_info.classes:
  @@ -139,7 +140,8 @@ def _build_class_page(page_info):
  parts.append(prop_info.doc.docstring)
  parts.append(_build_function_details(prop_info.doc.function_details))
  - assert not prop_info.doc.compatibility
  + parts.append(_build_compatibility(prop_info.doc.compatibility))
  +
  parts.append('\n\n')
  parts.append('\n\n')
  @@ -206,6 +208,8 @@ def _build_module_page(page_info):
  parts.append(str(page_info.defined_in))
  parts.append(page_info.doc.docstring)
  + parts.append(_build_compatibility(page_info.doc.compatibility))
  +
  parts.append('\n\n')
  if page_info.modules:
  