fix formatting

Author: tschie

src/main/java/com/esri/samples/symbology/simple_fill_symbol/README.md

@@ -1,4 +1,4 @@
-<h2>Simple Fill Symbol</h2>
+<h1>Simple Fill Symbol</h1>
 
 <p>Change a graphic's fill color, outline, and style properties.</p>
 

src/main/java/com/esri/samples/symbology/simple_line_symbol/README.md

@@ -1,4 +1,4 @@
-<h2>Simple Line Symbol</h2>
+<h1>Simple Line Symbol</h1>
 
 <p>Change a line graphic's color and style.</p>
 

src/main/java/com/esri/samples/symbology/simple_marker_symbol/README.md

@@ -1,4 +1,4 @@
-<h2>Simple Marker Symbol</h2>
+<h1>Simple Marker Symbol</h1>
 
 <p>Show simple markers.</p>
 

src/main/java/com/esri/samples/symbology/simple_renderer/README.md

@@ -1,4 +1,4 @@
-<h2>Simple Renderer</h2>
+<h1>Simple Renderer</h1>
 
 <p>Set default symbols for all graphics in an overlay.</p>