Bump ES target version to ES2022 (matrix-org#4264)

* Bump ES target version to ES2022

I want to be able to use `WeakRef`, and per
element-hq/element-web#24913 (comment),
I believe this should be safe.

* room.ts: Fix initialisation order

It seems that ES2022 causes typescript to change the initialization order of
regular properties vs parameter properties
(microsoft/TypeScript#45995), so we need to rearrange
the initializations to avoid an error.

In practice, it might be fine because we have enabled
`babel-plugin-transform-class-properties`, which moves the initialization back
after the parameter property, but we shoudn't rely on that, and anyway it
upsets the linter.

src/models/room.ts

@@ -398,7 +398,8 @@ export class Room extends ReadReceipt<RoomEmittedEvents, RoomEventHandlerMap> {
      *             Use getLiveTimeline().getState(EventTimeline.FORWARDS) instead.
      */
     public currentState!: RoomState;
-    public readonly relations = new RelationsContainer(this.client, this);
+
+    public readonly relations;
 
     /**
      * A collection of events known by the client
@@ -460,6 +461,7 @@ export class Room extends ReadReceipt<RoomEmittedEvents, RoomEventHandlerMap> {
         private readonly opts: IOpts = {},
     ) {
         super();
+
         // In some cases, we add listeners for every displayed Matrix event, so it's
         // common to have quite a few more than the default limit.
         this.setMaxListeners(100);
@@ -470,6 +472,8 @@ export class Room extends ReadReceipt<RoomEmittedEvents, RoomEventHandlerMap> {
         this.name = roomId;
         this.normalizedName = roomId;
 
+        this.relations = new RelationsContainer(this.client, this);
+
         // Listen to our own receipt event as a more modular way of processing our own
         // receipts. No need to remove the listener: it's on ourself anyway.
         this.on(RoomEvent.Receipt, this.onReceipt);

tsconfig.json

@@ -1,6 +1,6 @@
 {
     "compilerOptions": {
-        "target": "es2016",
+        "target": "es2022",
         "experimentalDecorators": true,
         "esModuleInterop": true,
         "module": "commonjs",