Fixed "FileStorage (minor) error in doc (Feature #3151)"

It was just a typo in the documentation.

modules/core/doc/xml_yaml_persistence.rst

@@ -11,7 +11,7 @@ You can store and then restore various OpenCV data structures to/from XML (http:
 
 Use the following procedure to write something to XML or YAML:
  #. Create new :ocv:class:`FileStorage` and open it for writing. It can be done with a single call to :ocv:func:`FileStorage::FileStorage` constructor that takes a filename, or you can use the default constructor and then call :ocv:func:`FileStorage::open`. Format of the file (XML or YAML) is determined from the filename extension (".xml" and ".yml"/".yaml", respectively)
- #. Write all the data you want using the streaming operator ``>>``, just like in the case of STL streams.
+ #. Write all the data you want using the streaming operator ``<<``, just like in the case of STL streams.
  #. Close the file using :ocv:func:`FileStorage::release`. ``FileStorage`` destructor also closes the file.
 
 Here is an example: ::