move accessibility to top level section

Author: tomcrane

source/presentation/4.0/index.md

@@ -1360,9 +1360,7 @@ Interactive examples are provided as recipes in the [IIIF Cookbook][annex-cookbo
 While all Annotation Page [`items`][prezi-40-model-items] are inherently ordered, an Annotation Page with the [`behavior`][prezi-40-model-behavior] "sequence" is explicitly a narrative, and clients should prevent (dissuade) users from jumping about - the annotations, and the effects of them _activating_ other contents of the Container, are intended to be experienced in order and individually. Normally, a client might display all the comments in an Annotation Page in a sidebar so they are all visible in the UI, but for an Annotation Page with [`behavior`][prezi-40-model-behavior] "sequence" only show the currently active annotation text, and next and previous UI.
 
 
-# Additional Features
-
-## Accessibility
+# Accessibility
 
 Some IIIF resources have associated resources, such as closed-caption files for video, audio descriptions for images, or tactile graphics for visual materials, that improve access to the content for a wider range of users. These linked resources play a specific accessibility-related role relative to the resource they describe or supplement. See [A/V Use Case 5: Movie with subtitles](#use-case-5-movie-with-subtitles) above.
 
@@ -1403,6 +1401,8 @@ Properties: [provides](model/#provides)
 {: .note}
 
 
+# Additional Features
+
 ## Services
 
 In many of the examples in this specification an image resource has an associated [IIIF Image API][image-api] Service. This is the most common use of [`service`][prezi-40-model-service] in IIIF, but other types of service are defined by IIIF specifications or available as extensions. Rather than just offer the link for download, the client is expected to interact with the service on the user's behalf. For the Image API, this usually means generating multiple requests for image tiles at the appropriate zoom level. For the [IIIF Search API][search-api], this means accepting user query terms, sending them to the search service endpoint, and rendering the results for further interaction (typically navigation to the result location within the Manifest).