Doc: Describe renaming files when renaming symbols

If the symbol is a class, and filenames contain the symbol,
Qt Creator also offers to rename the files.

Change-Id: Iba467cc4bf5ec6d4098973c9d391ffaff2f3bc4b
Reviewed-by: André Hartmann <aha_1980@gmx.de>
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@qt.io>

doc/src/editors/creator-editors.qdoc

@@ -1956,6 +1956,9 @@
 
     \section1 Renaming Symbols
 
+    You can rename symbols in all files in a project. When you rename a class,
+    you can also change filenames that match the class name.
+
     To rename a specific symbol in a Qt project:
 
     \list 1
@@ -1973,15 +1976,18 @@
             \image qtcreator-refactoring-replace.png
 
         \li To replace all selected instances, enter the name of the new symbol
-            in the \uicontrol {Replace with} text box and click
-            \uicontrol Replace.
+            in the \uicontrol {Replace with} text box.
 
             To omit an instance, uncheck the check-box next to the instance.
 
+        \li If the symbol is a class, select the \uicontrol {Rename files} check
+            box to also change the filenames that match the class name.
+
+        \li  Select \uicontrol Replace.
+
             \note This action replaces all selected instances of the symbol in
             all files listed in the \uicontrol {Search Results} pane. You cannot
             undo this action.
-
     \endlist
 
     \note Renaming local symbols does not open the \uicontrol {Search Results}