reduce duplication and code improvements (#1707)

* reduce code duplication

* reduce duplication, fix license headers

* simplify code

* typings fixes

* update tests

* minor fixes

* markdown fixes

* revert changes

docs/ja/tutorials/dialog-actions.md

@@ -19,9 +19,7 @@ ng g component dialogs/my-extension-dialog --module=app
 
 ```ts
 @NgModule({
-  imports: [...],
   declarations: [
-    ...,
     MyExtensionDialogComponent
   ]
 })
@@ -80,15 +78,11 @@ import { ShowMydDialogAction, SHOW_MY_DIALOG } from '../actions/app.actions';
 
 @Injectable()
 export class AppEffects {
-  constructor(...) {}
-
   @Effect({ dispatch: false })
   showMyDialog$ = this.actions$.pipe(
     ofType<ShowMydDialogAction>(SHOW_MY_DIALOG),
     map(() => {})
   );
-
-  // ...
 }
 ```
 
@@ -104,10 +98,7 @@ import { MyExtensionDialogComponent } from '../../dialogs/my-extension-dialog/my
 
 @Injectable()
 export class AppEffects {
-  constructor(
-    ...,
-    private dialog: MatDialog
-  ) {}
+  constructor(private dialog: MatDialog) {}
 
   @Effect({ dispatch: false })
   showMyDialog$ = this.actions$.pipe(
@@ -116,9 +107,6 @@ export class AppEffects {
       this.dialog.open(MyExtensionDialogComponent)
     })
   );
-
-  ...
-
 }
 ```
 
@@ -128,8 +116,6 @@ export class AppEffects {
 
 ```json
 {
-  ...,
-
   "features": {
     "toolbar": [
       {