fix(docs): correct dead links in commands pages (#993)

Author: MikeMcC399

app/commands/assertions.html

@@ -136,7 +136,7 @@ <h4 id="should"><a href="https://on.cypress.io/should" target="_blank">.should()
   .should('be.visible')</code></pre>
 
             <p>Note: find even more examples of matching element's text content in this
-              <a href="https://on.cypress.io/using-cypress-faq#How-do-I-get-an-element’s-text-contents" target="_blank">FAQ answer</a>.
+              <a href="https://docs.cypress.io/app/faq#How-do-I-get-an-elements-text-contents" target="_blank">FAQ answer</a>.
             </p>
           </div>
           <div class="col-xs-5">

app/commands/spies-stubs-clocks.html

@@ -44,7 +44,7 @@
               <li><a href="/commands/aliasing">Aliasing</a></li>
               <li><a href="/commands/waiting">Waiting</a></li>
               <li><a href="/commands/network-requests">Network Requests</a></li>
-              <li><a href="/commands/fixtures">Fixtures</a></li>
+              <li><a href="/commands/files">Files</a></li>
               <li><a href="/commands/storage">Storage</a></li>
               <li><a href="/commands/cookies">Cookies</a></li>
               <li class="active"><a href="/commands/spies-stubs-clocks">Spies, Stubs &amp; Clocks</a></li>