fix method name (beforeResolve)

Author: yyx990803

src/index.js

@@ -122,7 +122,7 @@ export default class VueRouter {
     this.beforeHooks.push(fn)
   }
 
-  onResolve (fn: Function) {
+  beforeResolve (fn: Function) {
     this.resolveHooks.push(fn)
   }
 

types/router.d.ts

@@ -21,7 +21,7 @@ declare class VueRouter {
   currentRoute: Route;
 
   beforeEach (guard: NavigationGuard): void;
-  onResolve (guard: NavigationGuard): void;
+  beforeResolve (guard: NavigationGuard): void;
   afterEach (hook: (to: Route, from: Route) => any): void;
   push (location: RawLocation, onComplete?: Function, onAbort?: Function): void;
   replace (location: RawLocation, onComplete?: Function, onAbort?: Function): void;