Parse the object's docstring and return a DocstringInfo.

This function clears @@'s from the docstring, and replaces `` references with links.

py_object A python object to retrieve the docs for (class, function/method, or module).
full_name (optional) The api path to the current object, so replacements can depend on context.
parser_config An instance of config.ParserConfig.
extra_docs Extra docs for symbols like public constants(list, tuple, etc) that need to be added to the markdown pages created.

A DocstringInfo object, all fields will be empty if no docstring was found.