docs: replaced the html tags with the updated ones (#50403)

PR Close #50403

aio/content/examples/component-interaction/src/app/app.component.html

@@ -2,10 +2,10 @@ <h1 id="top">Component Communication Cookbook</h1>
 
 <a href="#parent-to-child">Pass data from parent to child with input binding ("Heroes")</a><br/>
 <a href="#parent-to-child-setter">Intercept input property changes with a setter ("Master")</a><br/>
-<a href="#parent-to-child-on-changes">Intercept input property changes with <i>ngOnChanges</i> ("Source code version")</a><br/>
+<a href="#parent-to-child-on-changes">Intercept input property changes with <em>ngOnChanges</em> ("Source code version")</a><br/>
 <a href="#child-to-parent">Parent listens for child event ("Colonize Universe")</a><br/>
-<a href="#parent-to-child-local-var">Parent to child via <i>local variable</i>("Countdown to Liftoff")</a><br/>
-<a href="#parent-to-view-child">Parent calls <i>ViewChild</i>("Countdown  to Liftoff")</a><br/>
+<a href="#parent-to-child-local-var">Parent to child via <em>local variable</em>("Countdown to Liftoff")</a><br/>
+<a href="#parent-to-view-child">Parent calls <em>ViewChild</em>("Countdown  to Liftoff")</a><br/>
 <a href="#bidirectional-service">Parent and children communicate via a service ("Mission Control")</a><br/>
 
 <div id="parent-to-child">

aio/content/examples/forms/src/app/hero-form/hero-form.component.html

@@ -49,13 +49,13 @@ <h1>Hero Form</h1>
       <button type="button" class="btn btn-default" (click)="newHero(); heroForm.reset()">New Hero</button>
       <!-- #enddocregion new-hero-button-form-reset -->
  <!-- #enddocregion final -->
-      <i>with</i> reset
+      <em>with</em> reset
 
       &nbsp;&nbsp;
       <!-- #docregion new-hero-button-no-reset -->
       <button type="button" class="btn btn-default" (click)="newHero()">New Hero</button>
       <!-- #enddocregion new-hero-button-no-reset -->
-      <i>without</i> reset
+      <em>without</em> reset
 
      <!-- NOT SHOWN IN DOCS -->
       <div>

aio/content/examples/getting-started-v0/src/app/top-bar/top-bar.component.html

@@ -2,4 +2,4 @@
   <h1>My Store</h1>
 </a>
 
-<a class="button fancy-button"><i class="material-icons">shopping_cart</i>Checkout</a>
+<a class="button fancy-button"><em class="material-icons">shopping_cart</em>Checkout</a>

aio/content/marketing/presskit.html

@@ -441,7 +441,7 @@ <h2>Brand Names</h2>
 
     <h3>Angular</h3>
     <p>
-      The name <b>Angular</b> represents the work and promises provided to you by the Angular team.
+      The name <strong>Angular</strong> represents the work and promises provided to you by the Angular team.
     </p>
     <p>
       When not specified, Angular is assumed to be referring to the latest and greatest stable version from the Angular
@@ -450,20 +450,20 @@ <h3>Angular</h3>
 
     <h4>Example</h4>
     <p>
-      <b>Version v4.1 now available</b> - We are pleased to announce that the latest release of Angular is now
+      <strong>Version v4.1 now available</strong> - We are pleased to announce that the latest release of Angular is now
       available. Staying up to date is easy!
     </p>
 
     <h4>Example</h4>
     <p>
-      <b>Correct:</b> "New <code>*ngIf</code> capabilities&mdash;new in version 4.0 is the ability to ..."
+      <strong>Correct:</strong> "New <code>*ngIf</code> capabilities&mdash;new in version 4.0 is the ability to ..."
     </p>
     <p>
       <b class="error-text">Incorrect:</b> "New <code>*ngIf</code> capabilities in Angular 4&mdash;Angular 4 introduces
       the ability to ..."
     </p>
     <p>
-      <b>Reasoning</b>
+      <strong>Reasoning</strong>
     </p>
     <p>
       By not using "Angular 4" in the title, the content still feels applicable and useful after version 5, 6, 7 have
@@ -472,7 +472,7 @@ <h4>Example</h4>
 
     <h3>AngularJS</h3>
     <p>
-      <b>AngularJS</b> is the v1.x series of work and promises provided by the Angular team.
+      <strong>AngularJS</strong> is the v1.x series of work and promises provided by the Angular team.
     </p>
 
     <h4>Examples</h4>
@@ -505,7 +505,7 @@ <h3>AngularJS Material</h3>
 
     <h3>3rd Party Projects</h3>
     <p>
-      <b>X for Angular</b>
+      <strong>X for Angular</strong>
     </p>
     <p>
       3rd parties should use the terminology “X for Angular” or “ng-X” for software projects. Projects should avoid the
@@ -520,7 +520,7 @@ <h3>3rd Party Projects</h3>
       Where a codename or shortname is used, such as on npm or GitHub, some are acceptable, some are not acceptable.
     </p>
 
-    <b>Do not use</b>
+    <strong>Do not use</strong>
     <ul>
       <li><code>ng2-</code></li>
       <li><code>angular2-</code></li>