Fix example in a docstring to not use 'file' as a variable name
diff --git a/Lib/lib-tk/FileDialog.py b/Lib/lib-tk/FileDialog.py
index bd62c6d..323dc29 100644
--- a/Lib/lib-tk/FileDialog.py
+++ b/Lib/lib-tk/FileDialog.py
@@ -25,8 +25,8 @@
     Usage:
 
         d = FileDialog(master)
-        file = d.go(dir_or_file, pattern, default, key)
-        if file is None: ...canceled...
+        fname = d.go(dir_or_file, pattern, default, key)
+        if fname is None: ...canceled...
         else: ...open file...
 
     All arguments to go() are optional.