DOC: missing closing bracket (#56811)

added missing bracket

Author: svrashank

doc/source/development/contributing_docstring.rst

@@ -939,7 +939,7 @@ Each shared docstring will have a base template with variables, like
 Finally, docstrings can also be appended to with the ``doc`` decorator.
 
 In this example, we'll create a parent docstring normally (this is like
-``pandas.core.generic.NDFrame``. Then we'll have two children (like
+``pandas.core.generic.NDFrame``). Then we'll have two children (like
 ``pandas.core.series.Series`` and ``pandas.core.frame.DataFrame``). We'll
 substitute the class names in this docstring.