Have Media db return optional content_type, conversion fixes

src/client_server/media.rs

@@ -66,7 +66,7 @@ pub async fn get_content_route(
     {
         Ok(get_content::Response {
             file,
-            content_type: Some(content_type),
+            content_type,
             content_disposition: filename,
         }
         .into())
@@ -116,11 +116,7 @@ pub async fn get_content_thumbnail_route(
             .try_into()
             .map_err(|_| Error::BadRequest(ErrorKind::InvalidParam, "Width is invalid."))?,
     )? {
-        Ok(get_content_thumbnail::Response {
-            file,
-            content_type: Some(content_type),
-        }
-        .into())
+        Ok(get_content_thumbnail::Response { file, content_type }.into())
     } else if &*body.server_name != db.globals.server_name() && body.allow_remote {
         let get_thumbnail_response = server_server::send_request(
             &db.globals,

src/client_server/membership.rs

@@ -510,8 +510,7 @@ async fn join_room_by_id_helper(
             .expect("event is valid, we just created it"),
         );
 
-        // TODO fixup CanonicalJsonValue
-        // use that instead of serde_json::Map... maybe?
+        // Convert `serde_json;:Value` to `CanonicalJsonObj` for hashing/signing
         let mut canon_json_stub: BTreeMap<_, ruma::signatures::CanonicalJsonValue> =
             serde_json::from_value(join_event_stub_value).expect("json Value is canonical JSON");