Minor corrections on sidebar and home page

Author: dangerworm

_includes/sidebar.html

@@ -29,7 +29,7 @@
                 </li>
                 <li class="sidebar-dropdown">
                     <a href="{{site.url}}/about">
-                        <i class="fas fa-chalkboard-teacher"></i>
+                        <i class="fas fa-book-open"></i>
                         <span>About</span>
                     </a>
                 </li>

index.html

@@ -99,7 +99,7 @@ <h4>
     </div>
     <div class="col-sm-9 col-md-10 intro-text">
         <p>
-            We send out annoucements and updates from time to time. The best way to hear about what we're doing is to
+            We send out announcements and updates from time to time. The best way to hear about what we're doing is to
             sign up to our mailing list using the form on our <a href="contact">contact page</a>.
         </p>
     </div>