Apply suggestions from code review

Co-authored-by: Johannes Marbach <n0-0ne+github@mailbox.org>

proposals/3765-rich-room-topics.md

@@ -25,11 +25,11 @@ events as shown below[^1].
   "state_key": "",
   "content": {
     "m.topic": {
-      "m.text": [{
-        "body": "All about **pizza** | [Recipes](https://recipes.pizza.net)"
-      }, {
+      "m.text": [ {
         "mimetype": "text/html",
         "body": "All about <b>pizza</b> | <a href=\"https://recipes.pizza.net\">Recipes</a>"
+      }, {
+        "body": "All about **pizza** | [Recipes](https://recipes.pizza.net)"
       }]
     },
     "topic": "All about **pizza** | [Recipes](https://recipes.pizza.net)"
@@ -38,16 +38,18 @@ events as shown below[^1].
 }
 ```
 
-Details of how `m.text` works may be found in [MSC1767] and are not
-repeated here.
+In line with [MSC1767], clients should render the first mime type in the
+array that they understand. Further details of how `m.text` works may
+be found in [MSC1767] and are not repeated here.
 
 The wrapping `m.topic` content block is similar to `m.caption` for file
 uploads as defined in [MSC3551]. It avoids clients accidentally rendering
-the topic as a room message. Note that while [MSC1767] had explicitly
-excluded state events from being treated as extensible, this is being
-changed with [MSC4252]. The extra content block, therefore, allows putting
+the topic as a room message. ([MSC1767] specifies that unknown events with
+an `m.text` content block should be rendered as a regular room message, and
+while [MSC1767] had explicitly excluded state events from being treated as 
+extensible, this is being changed with [MSC4252].) The extra content block, therefore, allows putting
 a fallback representation that is actually designated for the timeline
-into a separate `content['m.text']` field. Lastly, the `m.topic` content
+into a separate `content['m.text']` field. In addition, the `m.topic` content
 block also serves as a good place for additional fields to be added by
 other MSCs in the future.
 
@@ -112,15 +114,13 @@ for unsafe HTML.
 ## Unstable prefix
 
 While this MSC is not considered stable, `m.topic` should be referred to
-as `org.matrix.msc3765.topic`. Note that extensible events and content
-blocks might have their own prefixing requirements.
+as `org.matrix.msc3765.topic`.
 
 [^1]: A future MSC may discuss how to adopt the `m.topic` content block in
       new room versions which support extensible events.
 
 [plain text]: https://spec.matrix.org/v1.12/client-server-api/#mroomtopic
 [MSC1767]: https://github.com/matrix-org/matrix-spec-proposals/pull/1767
-[MSC3551]: https://github.com/matrix-org/matrix-spec-proposals/pull/3551
 [MSC4252]: https://github.com/matrix-org/matrix-spec-proposals/pull/4252
 [sanitise]: https://spec.matrix.org/v1.12/client-server-api/#security-considerations
 [server side search]: https://spec.matrix.org/v1.12/client-server-api/#server-side-search