Added comments

android/src/main/java/com/flutter_webview_plugin/WebviewManager.java

@@ -122,19 +122,25 @@ class WebviewManager {
             }
         });
     }
-
+    /** 
+    * Reloads the Webview.
+    */
     void reload(MethodCall call, MethodChannel.Result result) {
         if (webView != null) {
             webView.reload();
         }
     }
-
+    /** 
+    * Navigates back on the Webview.
+    */
     void back(MethodCall call, MethodChannel.Result result) {
         if (webView != null && webView.canGoBack()) {
             webView.goBack();
         }
     }
-
+    /** 
+    * Navigates forward on the Webview.
+    */
     void forward(MethodCall call, MethodChannel.Result result) {
         if (webView != null && webView.canGoForward()) {
             webView.goForward();
@@ -144,11 +150,15 @@ class WebviewManager {
     void resize(FrameLayout.LayoutParams params) {
         webView.setLayoutParams(params);
     }
-
+    /** 
+    * Checks if going back on the Webview is possible.
+    */
     boolean canGoBack() {
         return webView.canGoBack();
     }
-
+    /** 
+    * Checks if going forward on the Webview is possible.
+    */
     boolean canGoForward() {
         return webView.canGoForward();
     }