Doc: hiding detailed progress information

Add an image that shows the current location of the
progress bar and the button.

Change-Id: I2292721e6215d056a6eedab3ed5dd9485ec0776f
Reviewed-by: Eike Ziller <eike.ziller@digia.com>

doc/src/projects/creator-projects-opening.qdoc

@@ -79,5 +79,9 @@
     \QC parses all the source files in the project and performs a semantic
     analysis to build up the information that it needs for functions such as
     navigation and finding usages. A progress bar is displayed during parsing.
+    To show or hide detailed progress information, select
+    \gui {Toggle Progress Details} (1).
+
+    \image creator-toggle-progress-bar.png "Toggle Progress Details button"
 
 */