Fix exception handling example

php.html.markdown

@@ -837,11 +837,14 @@ try {
     // Handle exception
 }
 
-// When using try catch blocks in a namespaced environment use the following
+// When using try catch blocks in a namespaced environment it is important to
+// escape to the global namespace, because Exceptions are classes, and the
+// Exception class exists in the global namespace. This can be done using a
+// leading backslash to catch the Exception.
 
 try {
     // Do something
-} catch (Exception $e) {
+} catch (\Exception $e) {
     // Handle exception
 }