Update measuring context help to reflect changes in svn r6153 and r6154

git-svn-id: http://svn.osgeo.org/qgis/trunk@6155 c8812cc2-4d05-0410-92ff-de0c093fc19c

Author: g_j_m

resources/context_help/687883780_en_US

@@ -1,5 +1,5 @@
 <h3>Measure Tools</h3>
-There are two measure tools: length and area. Currently the tools provide results in metric units only.
+There are two measure tools: length and area. Currently the tools provide results in metric units only. A single right mouse click stops the measuring, while two right mouse clicks starts measuring anew.
 <h4>Measuring Lengths</h4>
 To measure lengths, select the tool and click along the path you want to measure. The length of each segment is displayed as is the total length for the path.  With the measure tool, you can measure both distances and areas on the map canvas.
 <h4>Measuring Areas</h4>