Fix an issue in the diff parser

Forgot to check for functions/classes that were part of a decorator/async func.

Fixes https://github.com/davidhalter/jedi/issues/1132

test/test_diff_parser.py

@@ -507,3 +507,22 @@ def test_endmarker_newline(differ):
 def test_newlines_at_end(differ):
     differ.initialize('a\n\n')
     differ.parse('a\n', copies=1)
+
+
+def test_end_newline_with_decorator(differ):
+    code = dedent('''\
+        @staticmethod
+        def spam():
+            import json
+            json.l''')
+
+    differ.initialize(code)
+    module = differ.parse(code + '\n', copies=0)
+    decorated, endmarker = module.children
+    assert decorated.type == 'decorated'
+    decorator, func = decorated.children
+    suite = func.children[-1]
+    assert suite.type == 'suite'
+    newline, first_stmt, second_stmt = suite.children
+    assert first_stmt.get_code() == '    import json\n'
+    assert second_stmt.get_code() == '    json.l\n'