Drop features and APIs deprecated in 1.8

tests/roots/test-add_source_parser/conf.py

@@ -1,17 +1,8 @@
 import os
 import sys
 
-from docutils.parsers import Parser
-
 sys.path.insert(0, os.path.abspath('.'))
 
 
-class DummyMarkdownParser(Parser):
-    supported = ('markdown',)
-
-
 extensions = ['source_parser']
-source_suffix = ['.rst', '.md']
-source_parsers = {
-    '.md': DummyMarkdownParser
-}
+source_suffix = ['.rst']