fix autolink error that occurs when "See Also" line is succeeded by "--------" (#197)

* mat_types.py: fix bug when parsing mlapp files that have no description

* fix autolink error that occurs when "See Also" line is succeeded by "--------" 

This usually happens when using numpy syntax docstrings.

Author: luhuhis

sphinxcontrib/mat_documenters.py

@@ -203,7 +203,8 @@ def auto_link_see_also(self, docstrings):
                     if is_see_also_line:
                         # find name
                         match = see_also_cond_re.search(line)
-                        entries_str = match.group(2)  # the entries
+                        if match is not None:
+                            entries_str = match.group(2)  # the entries
                     elif match := see_also_re.search(line):
                         is_see_also_line = True  # line begins with "See also"
                         entries_str = match.group(2)  # the entries