docs: add possibility to reset 12-hours option

Author: json-derulo

Diff for: projects/angular-intl-demo/src/app/pipes/date/date.component.html

@@ -29,9 +29,14 @@
     </mat-select>
   </mat-form-field>
 
-  <mat-slide-toggle [(ngModel)]="hour12">
-    12 Hours
-  </mat-slide-toggle>
+  <mat-form-field>
+    <mat-label>12 Hours</mat-label>
+    <mat-select [(ngModel)]="hour12">
+      <mat-option [value]="undefined">Browser default</mat-option>
+      <mat-option [value]="true">true</mat-option>
+      <mat-option [value]="false">false</mat-option>
+    </mat-select>
+  </mat-form-field>
 </div>
 
 <p>{{selectedDate | intlDate: {dateStyle, timeStyle, hour12, locale} }}</p>

Diff for: projects/angular-intl-demo/src/app/pipes/pipes.module.ts

@@ -10,7 +10,6 @@ import {MatTabsModule} from "@angular/material/tabs";
 import {IntlModule} from "projects/angular-ecmascript-intl/src/lib/intl.module";
 import {MatSelectModule} from "@angular/material/select";
 import {FormsModule} from "@angular/forms";
-import {MatSlideToggleModule} from "@angular/material/slide-toggle";
 import {MatInputModule} from "@angular/material/input";
 import {PipesRoutingModule} from "./pipes-routing.module";
 
@@ -30,7 +29,6 @@ import {PipesRoutingModule} from "./pipes-routing.module";
     IntlModule,
     MatSelectModule,
     FormsModule,
-    MatSlideToggleModule,
     MatInputModule,
   ],
 })