Merge pull request jupyter#3228 from ns23/update-alt-text

[WIP] Updated image alt text in notebook.html

Author: takluyver

notebook/templates/notebook.html

@@ -46,7 +46,7 @@
 
 <span id="kernel_logo_widget">
   {% block kernel_logo_widget %}
-  <img class="current_kernel_logo" src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7"/>
+  <img class="current_kernel_logo" alt="Current Kernel Logo" src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7"/>
   {% endblock %}
 </span>