oops, forget adding document

Author: rhysd

doc/clang-format.txt

@@ -156,6 +156,17 @@ g:clang_format#auto_format                          *g:clang_format#auto_format*
     buffer on saving the buffer.  Formatting is executed at |BufWritePre| event.
     The default value is 0.
 
+g:clang_format#auto_format_on_insert_leave
+                                    *g:clang_format#auto_format_on_insert_leave*
+
+    When the value is 1, the inserted lines are automatically formatted on
+    leaving insert mode.  Formatting is executed on |InsertLeave| event.
+
+    Below link is a screenshot of an example for this feature.  Inserted 'if'
+    statement is automatically formated on leaving insert mode.
+
+    http://gifzo.net/CPrVbHnKMe.gif
+
 ==============================================================================
 SETUP EXAMPLE                                   *vim-clang-format-setup-example*