chore: remove unused methods (#29475)

Co-authored-by: Shelley Vohr <[email protected]>

typings/internal-electron.d.ts

@@ -57,10 +57,6 @@ declare namespace Electron {
 
   interface WebContents {
     _loadURL(url: string, options: ElectronInternal.LoadURLOptions): void;
-    _stop(): void;
-    _goBack(): void;
-    _goForward(): void;
-    _goToOffset(offset: number): void;
     getOwnerBrowserWindow(): Electron.BrowserWindow;
     getWebPreferences(): Electron.WebPreferences;
     getLastWebPreferences(): Electron.WebPreferences;