Fix a minor grammar issue in the logging cookbook (pythonGH-3136)

Doc/howto/logging-cookbook.rst

@@ -1055,7 +1055,7 @@ to indicate additional contextual information to be added to the log). So
 you cannot directly make logging calls using :meth:`str.format` or
 :class:`string.Template` syntax, because internally the logging package
 uses %-formatting to merge the format string and the variable arguments.
-There would no changing this while preserving backward compatibility, since
+There would be no changing this while preserving backward compatibility, since
 all logging calls which are out there in existing code will be using %-format
 strings.