Fix strange reportings of line numbers for warnings generated from

autodoc-included docstrings, due to different behavior depending
on docutils version.

tests/root/autodoc.txt

@@ -26,3 +26,9 @@ Just testing a few autodoc possibilities...
 .. autoclass:: CustomDict
    :show-inheritance:
    :members:
+
+
+.. automodule:: autodoc_fodder
+   :noindex:
+
+   .. autoclass:: MarkupError

tests/test_build_html.py

@@ -31,6 +31,9 @@ def teardown_module():
 html_warnfile = StringIO()
 
 ENV_WARNINGS = """\
+%(root)s/autodoc_fodder.py:docstring of autodoc_fodder\\.MarkupError:2: \
+\\(WARNING/2\\) Explicit markup ends without a blank line; unexpected \
+unindent\\.\\n?
 %(root)s/images.txt:9: WARNING: image file not readable: foo.png
 %(root)s/images.txt:23: WARNING: nonlocal image URI found: \
 http://www.python.org/logo.png