Improve code formatting and fix a few typos in docs (#11221)

* Labeled a lot more code blocks with the appropriate type
* Fixed a couple of minor typos (missing/extraneous commas)

Signed-off-by: Sumner Evans <me@sumnerevans.com>

4 files changed, 8 insertions, 8 deletions

diff --git a/docs/admin_api/event_reports.md b/docs/admin_api/event_reports.md

index 3abb06099c..f523774ba8 100644
--- a/docs/admin_api/event_reports.md
+++ b/docs/admin_api/event_reports.md
@@ -99,7 +99,7 @@ server admin: see [Admin API](../usage/administration/admin_api).
 
 It returns a JSON body like the following:
 
-```jsonc
+```json
 {
     "event_id": "$bNUFCwGzWca1meCGkjp-zwslF-GfVcXukvRLI1_FaVY",
     "event_json": {
@@ -132,7 +132,7 @@ It returns a JSON body like the following:
         },
         "type": "m.room.message",
         "unsigned": {
-            "age_ts": 1592291711430,
+            "age_ts": 1592291711430
         }
     },
     "id": <report_id>,
diff --git a/docs/admin_api/purge_history_api.md b/docs/admin_api/purge_history_api.md

index 13b991eacf..bd29e29ab8 100644
--- a/docs/admin_api/purge_history_api.md
+++ b/docs/admin_api/purge_history_api.md
@@ -27,7 +27,7 @@ Room state data (such as joins, leaves, topic) is always preserved.
 
 To delete local message events as well, set `delete_local_events` in the body:
 
-```
+```json
 {
    "delete_local_events": true
 }
diff --git a/docs/admin_api/room_membership.md b/docs/admin_api/room_membership.md

index 8a5ce191df..548b790a5c 100644
--- a/docs/admin_api/room_membership.md
+++ b/docs/admin_api/room_membership.md
@@ -28,7 +28,7 @@ server admin: see [Admin API](../usage/administration/admin_api).
 
 Response:
 
-```
+```json
 {
   "room_id": "!636q39766251:server.com"
 }
diff --git a/docs/admin_api/rooms.md b/docs/admin_api/rooms.md

index 8e524e6509..acf1cab2a2 100644
--- a/docs/admin_api/rooms.md
+++ b/docs/admin_api/rooms.md
@@ -87,7 +87,7 @@ GET /_synapse/admin/v1/rooms
 
 A response body like the following is returned:
 
-```jsonc
+```json
 {
   "rooms": [
     {
@@ -170,7 +170,7 @@ GET /_synapse/admin/v1/rooms?order_by=size
 
 A response body like the following is returned:
 
-```jsonc
+```json
 {
   "rooms": [
     {
@@ -208,7 +208,7 @@ A response body like the following is returned:
     }
   ],
   "offset": 0,
-  "total_rooms": 150
+  "total_rooms": 150,
   "next_token": 100
 }
 ```
@@ -224,7 +224,7 @@ GET /_synapse/admin/v1/rooms?order_by=size&from=100
 
 A response body like the following is returned:
 
-```jsonc
+```json
 {
   "rooms": [
     {