Add references to PEPs 691, 700, and 714 to the simple repository API spec page

Author: brettcannon

source/specifications/simple-repository-api.rst

@@ -5,9 +5,16 @@
 Simple repository API
 =====================
 
-The current interface for querying available package versions and
-retrieving packages from an index server is defined in :pep:`503`,
-with the addition of "yank" support (allowing a kind of file deletion)
-in :pep:`592`, specifying the interface version provided
-by an index server in :pep:`629`, and providing package metadata
-independently from a package in :pep:`658`.
+The interface for querying available package versions and
+retrieving packages from an index server comes in two forms:
+HTML and JSON.
+
+The HTML format is defined in :pep:`503`, with the addition of "yank"
+support (allowing a kind of file deletion) in :pep:`592`, specifying
+the interface version provided by an index server in :pep:`629`, and
+providing package metadata independently from a package in
+:pep:`658` and revised in :pep:`714`.
+
+The JSON format is defined in :pep:`691`, with additional fields
+added in :pep:`700`, and revisions around providing package metadata
+independently from a package in :pep:`714`.