DM-11556 update title for heatmap chart.

Author: Cindy Wang

src/firefly/html/demo/ffapi-slate-test2.html

@@ -53,8 +53,10 @@
 </div>
 <pre>
     try:
-    148.88822;69.06529;EQ_J2000
-    202.48417;47.23056;EQ_J2000
+    148.88822;69.06529;EQ_J2000 # Galaxy M81
+    202.48417;47.23056;EQ_J2000 # Galaxy M51
+    136.9316774;+1.1195886;galactic # W5 star-forming region
+    10.68479;41.26906;EQ_J2000 # Galaxy M31
 </pre>
 
 
@@ -214,7 +216,7 @@
             ];
 
             var layoutHM = {
-                title: 'Photometry heatmap',
+                title: 'Magnitude-magnitude densities',
                 xaxis: {title: 'w1 photometry (mag)'},
                 yaxis: {title: ''}
             };