Enable @typescript-eslint/explicit-function-return-type in /src (#9788)

* Enable `@typescript-eslint/explicit-member-accessibility` on /src

* Prettier

* Enable `@typescript-eslint/explicit-function-return-type` in /src

* Fix types

* tsc strict fixes

* Delint

* Fix test

* Fix bad merge

src/settings/controllers/FontSizeController.ts

@@ -25,7 +25,7 @@ export default class FontSizeController extends SettingController {
         super();
     }
 
-    public onChange(level: SettingLevel, roomId: string, newValue: any) {
+    public onChange(level: SettingLevel, roomId: string, newValue: any): void {
         // Dispatch font size change so that everything open responds to the change.
         dis.dispatch<UpdateFontSizePayload>({
             action: Action.UpdateFontSize,

src/settings/controllers/NotificationControllers.ts

@@ -64,7 +64,7 @@ export class NotificationsEnabledController extends SettingController {
         return calculatedValue;
     }
 
-    public onChange(level: SettingLevel, roomId: string, newValue: any) {
+    public onChange(level: SettingLevel, roomId: string, newValue: any): void {
         if (getNotifier().supportsDesktopNotifications()) {
             getNotifier().setEnabled(newValue);
         }

src/settings/controllers/OrderedMultiController.ts

@@ -44,7 +44,7 @@ export class OrderedMultiController extends SettingController {
         return null; // no override
     }
 
-    public onChange(level: SettingLevel, roomId: string, newValue: any) {
+    public onChange(level: SettingLevel, roomId: string, newValue: any): void {
         for (const controller of this.controllers) {
             controller.onChange(level, roomId, newValue);
         }

src/settings/controllers/PushToMatrixClientController.ts

@@ -26,7 +26,7 @@ export default class PushToMatrixClientController extends SettingController {
         super();
     }
 
-    public onChange(level: SettingLevel, roomId: string, newValue: any) {
+    public onChange(level: SettingLevel, roomId: string, newValue: any): void {
         // XXX does this work? This surely isn't necessarily the effective value,
         // but it's what NotificationsEnabledController does...
         this.setter.call(MatrixClientPeg.get(), this.inverse ? !newValue : newValue);

src/settings/controllers/ReloadOnChangeController.ts

@@ -19,7 +19,7 @@ import PlatformPeg from "../../PlatformPeg";
 import { SettingLevel } from "../SettingLevel";
 
 export default class ReloadOnChangeController extends SettingController {
-    public onChange(level: SettingLevel, roomId: string, newValue: any) {
+    public onChange(level: SettingLevel, roomId: string, newValue: any): void {
         PlatformPeg.get().reload();
     }
 }

src/settings/controllers/SystemFontController.ts

@@ -26,7 +26,7 @@ export default class SystemFontController extends SettingController {
         super();
     }
 
-    public onChange(level: SettingLevel, roomId: string, newValue: any) {
+    public onChange(level: SettingLevel, roomId: string, newValue: any): void {
         // Dispatch font size change so that everything open responds to the change.
         dis.dispatch<UpdateSystemFontPayload>({
             action: Action.UpdateSystemFont,

src/settings/controllers/ThreadBetaController.tsx

@@ -55,7 +55,7 @@ export default class ThreadBetaController extends SettingController {
         return enable;
     }
 
-    public onChange(level: SettingLevel, roomId: string, newValue: any) {
+    public onChange(level: SettingLevel, roomId: string, newValue: any): void {
         // Requires a reload as we change an option flag on the `js-sdk`
         // And the entire sync history needs to be parsed again
         PlatformPeg.get().reload();

src/settings/controllers/UseSystemFontController.ts

@@ -26,7 +26,7 @@ export default class UseSystemFontController extends SettingController {
         super();
     }
 
-    public onChange(level: SettingLevel, roomId: string, newValue: any) {
+    public onChange(level: SettingLevel, roomId: string, newValue: any): void {
         // Dispatch font size change so that everything open responds to the change.
         dis.dispatch<UpdateSystemFontPayload>({
             action: Action.UpdateSystemFont,