STY: Fix typos

Documentation/Cookbook/rst/C++/Filters.rst

Documentation/Cookbook/rst/C++/UserGuide.rst

Documentation/Cookbook/rst/C++/WriteAnApplication.rst

Documentation/Cookbook/rst/CompilingOTBFromSource.rst

Documentation/Cookbook/rst/Monteverdi.rst

Documentation/Cookbook/rst/recipes/featextract.rst

Documentation/Cookbook/rst/recipes/stereo.rst

README.md

RELEASE_NOTES.txt