Fill out org scoped attestations API doc (#56464)

Signed-off-by: Meredith Lancaster <malancas@users.noreply.github.com>
Co-authored-by: Ben Ahmady <32935794+subatoi@users.noreply.github.com>

Author: malancas

content/rest/orgs/attestations.md

@@ -1,7 +1,7 @@
 ---
-title: TODOCS
-shortTitle: TODOCS
-intro: TODOCS
+title: REST API endpoints for artifact attestations
+shortTitle: Artifact attestations
+intro: Use the REST API to interact with artifact attestations.
 versions: # DO NOT MANUALLY EDIT. CHANGES WILL BE OVERWRITTEN BY A 🤖
   fpt: '*'
   ghec: '*'