Removing references to outdated video tutorials (#888)

Co-authored-by: Toby Hodges <tbyhdgs@gmail.com>

Author: sstevens2

_includes/install_instructions/shell.html

@@ -257,12 +257,6 @@ <h3>Installing Git for Windows</h3>
                   </li>
                 </ol>
                 <p>This will provide you with both Git and Bash in the Git Bash program.</p>
-                <h4>Video Tutorial</h4>
-                <div class="yt-wrapper2">
-                    <div class="yt-wrapper">
-                        <iframe type="text/html" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" src="https://www.youtube-nocookie.com/embed/339AEqk9c-8?modestbranding=1&playsinline=1&iv_load_policy=3&rel=0" class="yt-frame" allowfullscreen></iframe>
-                    </div>
-                </div>
             </article>
         </div>
       </article>
@@ -273,8 +267,6 @@ <h4>Video Tutorial</h4>
 	  Bash is available in all versions, so no need to install anything.
 	  You access Bash from the Terminal (found in
 	  <code>/Applications/Utilities</code>).
-          See the Git installation <a href="#shell-macos-video-tutorial">video tutorial</a>
-          for an example on how to open the Terminal.
           You may want to keep Terminal in your dock for this workshop.
         </p>
         <p>