Remove prev_batch

It wasn't particulalry useful for clients, and doesn't help equivocation much.

proposals/4354-sticky-events.md

@@ -53,8 +53,8 @@ with a valid value makes the event “sticky”[^stickyobj]. Valid values are th
 This key can be set by clients in the CS API by a new query parameter `stick_duration_ms`, which is
 added to the following endpoints:
 
-* `PUT /\_matrix/client/v3/rooms/{roomId}/send/{eventType}/{txnId}`
-* `PUT /\_matrix/client/v3/rooms/{roomId}/state/{eventType}/{stateKey}`
+* `PUT /_matrix/client/v3/rooms/{roomId}/send/{eventType}/{txnId}`
+* `PUT /_matrix/client/v3/rooms/{roomId}/state/{eventType}/{stateKey}`
 
 To calculate if any sticky event is still sticky:
 
@@ -97,9 +97,9 @@ The new sync section looks like:
         "ephemeral": { ... },
         "state": { ... },
         "timeline": { ... },
-        "sticky_events": [
+        "sticky_events": {
+            "events": [
                 {
-     "event": {
                     "sender": "@bob:example.com",
                     "type": "m.foo",
                     "sticky": {
@@ -108,10 +108,7 @@ The new sync section looks like:
                     "origin_server_ts": 1757920344000,
                     "content": { ... }
                 },
-     "prev_batch": "s1234_5678_90123"
-          },
                 {
-     "event": {
                     "sender": "@alice:example.com",
                     "type": "m.foo",
                     "sticky": {
@@ -119,10 +116,8 @@ The new sync section looks like:
                     },
                     "origin_server_ts": 1757920311020,
                     "content": { ... }
-     },
-     "prev_batch": "s1234_5678_90125"
                 }
-        ],
+            ]
         }
     }
   }
@@ -134,10 +129,8 @@ Over Simplified Sliding Sync, Sticky Events have their own extension `sticky_eve
 ```json
 {
   "rooms": {
-      "!726s6s6q:example.com": [
-        {
-          "prev_batch": "s1234_5678_90125",
-          "event": {
+      "!726s6s6q:example.com": {
+          "events": [{
               "sender": "@bob:example.com",
               "type": "m.foo",
               "sticky": {
@@ -145,10 +138,9 @@ Over Simplified Sliding Sync, Sticky Events have their own extension `sticky_eve
               },
               "origin_server_ts": 1757920344000,
               "content": { ... }
+          }]
       }
   }
-      ]
-  }
 }
 ```