Updated STL files in documentation

Author: rwb27

docs/openflexure microscope.docubricks.xml

@@ -395,7 +395,7 @@ There is a test file that prints a single leg of the microscope - the Microscope
           <file url="./images/all_printed_parts.jpg" />
           <file url="./stl/all_parts_picam2.stl" />
           <file url="./stl/bed1_tall_picam2.stl" />
-          <file url="./stl/bed2_shallow.stl" />
+          <file url="./stl/bed2_shallow_picam2.stl" />
         </media>
       </step>
       <step>