Fixed typo in django/core/cache/backends/base.py docstring.

    def make_key(self, key, version=None):

        """Constructs the key used by all other methods. By default it

        uses the key_func to generate a key (which, by default,

        prepends the `key_prefix' and 'version'). An different key

        prepends the `key_prefix' and 'version'). A different key

        function can be provided at the time of cache construction;

        alternatively, you can subclass the cache backend to provide

        custom key making behavior.