docs: updated the html tags (#27151)

(cherry picked from commit df8f827)

Author: aanchal88

src/cdk/menu/menu-item.spec.ts

@@ -176,7 +176,7 @@ class MenuItemWithIconClass {
 }
 
 @Component({
-  template: ` <button cdkMenuItem><b>Click</b> me!</button> `,
+  template: ` <button cdkMenuItem><strong>Click</strong> me!</button> `,
 })
 class MenuItemWithBoldElement {}
 
@@ -189,7 +189,7 @@ class MenuItemWithBoldElement {}
           Click
         </div>
         <mat-icon>menu</mat-icon>
-        <div>me<b>!</b></div>
+        <div>me<strong>!</strong></div>
       </div>
     </button>
   `,

src/components-examples/cdk/listbox/cdk-listbox-forms-validation/cdk-listbox-forms-validation-example.html

@@ -17,7 +17,7 @@
   <p *ngFor="let error of getErrors()">{{error}}</p>
 </div>
 <p>
-  Your zodiac sign is: <b>{{signCtrl.value | json}}</b>&nbsp;
+  Your zodiac sign is: <strong>{{signCtrl.value | json}}</strong>&nbsp;
   <button (click)="signCtrl.setValue(['Cat'])">Set: Cat</button>&nbsp;
   <button (click)="signCtrl.setValue(['Dragon', 'Snake'])">Set: Dragon, Snake</button>&nbsp;
   <button (click)="signCtrl.setValue(['Cat', 'Rat'])">Set: Cat, Rat</button>&nbsp;

src/components-examples/cdk/listbox/cdk-listbox-reactive-forms/cdk-listbox-reactive-forms-example.html

@@ -16,6 +16,6 @@
   <!-- #enddocregion listbox -->
 </div>
 <p>
-  Your preferred language: <b>{{languageCtrl.value | json}}</b>&nbsp;
+  Your preferred language: <strong>{{languageCtrl.value | json}}</strong>&nbsp;
   <button (click)="languageCtrl.reset()">Reset</button>
 </p>

src/components-examples/cdk/listbox/cdk-listbox-template-forms/cdk-listbox-template-forms-example.html

@@ -17,6 +17,6 @@
   <!-- #enddocregion listbox -->
 </div>
 <p>
-  Your order: <b>{{order | json}}</b>&nbsp;
+  Your order: <strong>{{order | json}}</strong>&nbsp;
   <button (click)="order = []">Reset</button>
 </p>

src/components-examples/cdk/listbox/cdk-listbox-value-binding/cdk-listbox-value-binding-example.html

@@ -17,6 +17,6 @@
   <!-- #enddocregion listbox -->
 </div>
 <p>
-  Your starter pokemon is <b>{{starter | json}}</b>&nbsp;
+  Your starter pokemon is <strong>{{starter | json}}</strong>&nbsp;
   <button (click)="reset()">Reset</button>
 </p>