Fix lints

src/room/GroupCallView.tsx

@@ -94,7 +94,7 @@ export const GroupCallView: FC<Props> = ({
 
   useEffect(() => {
     window.rtcSession = rtcSession;
-    return () => {
+    return (): void => {
       delete window.rtcSession;
     };
   }, [rtcSession]);
@@ -200,7 +200,7 @@ export const GroupCallView: FC<Props> = ({
         await widget!.api.transport.reply(ev.detail, {});
       };
       widget.lazyActions.on(ElementWidgetActions.JoinCall, onJoin);
-      return () => {
+      return (): void => {
         widget!.lazyActions.off(ElementWidgetActions.JoinCall, onJoin);
       };
     } else if (widget && !preload && skipLobby) {
@@ -255,7 +255,7 @@ export const GroupCallView: FC<Props> = ({
         await leaveRTCSession(rtcSession);
       };
       widget.lazyActions.once(ElementWidgetActions.HangupCall, onHangup);
-      return () => {
+      return (): void => {
         widget!.lazyActions.off(ElementWidgetActions.HangupCall, onHangup);
       };
     }

src/room/InCallView.tsx

@@ -97,7 +97,7 @@ export const ActiveCall: FC<ActiveCallProps> = (props) => {
   );
 
   useEffect(() => {
-    return () => {
+    return (): void => {
       livekitRoom?.disconnect();
     };
     // eslint-disable-next-line react-hooks/exhaustive-deps
@@ -220,7 +220,7 @@ export const InCallView: FC<InCallViewProps> = subscribe(
           onSpotlightLayout,
         );
 
-        return () => {
+        return (): void => {
           widget!.lazyActions.off(
             ElementWidgetActions.TileLayout,
             onTileLayout,

src/room/VideoPreview.tsx

@@ -110,7 +110,7 @@ export const VideoPreview: FC<Props> = ({
     if (videoEl.current) {
       videoTrack?.attach(videoEl.current);
     }
-    return () => {
+    return (): void => {
       videoTrack?.detach();
     };
   }, [videoTrack]);

src/room/useActiveFocus.ts

@@ -64,7 +64,7 @@ export function useActiveFocus(
       onMembershipsChanged,
     );
 
-    return () => {
+    return (): void => {
       rtcSession.off(
         MatrixRTCSessionEvent.MembershipsChanged,
         onMembershipsChanged,

src/room/usePageUnload.ts

@@ -50,7 +50,7 @@ export function usePageUnload(callback: () => void): void {
     // @ts-ignore
     window.addEventListener("beforeunload", onBeforeUnload);
 
-    return () => {
+    return (): void => {
       window.removeEventListener("pagehide", onBeforeUnload);
       // eslint-disable-next-line @typescript-eslint/ban-ts-comment
       // @ts-ignore