Replace deprecated "config.option.<name>" usages from docs

doc/en/example/attic.rst

@@ -17,7 +17,7 @@ example: specifying and selecting acceptance tests
 
     class AcceptFixture(object):
         def __init__(self, request):
-            if not request.config.option.acceptance:
+            if not request.config.getoption('acceptance'):
                 pytest.skip("specify -A to run acceptance tests")
             self.tmpdir = request.config.mktemp(request.function.__name__, numbered=True)
 

doc/en/example/parametrize.rst

@@ -36,7 +36,7 @@ Now we add a test configuration like this::
 
     def pytest_generate_tests(metafunc):
         if 'param1' in metafunc.fixturenames:
-            if metafunc.config.option.all:
+            if metafunc.config.getoption('all'):
                 end = 5
             else:
                 end = 2

doc/en/parametrize.rst

@@ -187,7 +187,7 @@ command line option and the parametrization of our test function::
     def pytest_generate_tests(metafunc):
         if 'stringinput' in metafunc.fixturenames:
             metafunc.parametrize("stringinput",
-                                 metafunc.config.option.stringinput)
+                                 metafunc.config.getoption('stringinput'))
 
 If we now pass two stringinput values, our test will run twice::
 

doc/en/writing_plugins.rst

@@ -331,11 +331,11 @@ string value of ``Hello World!`` if we do not supply a value or ``Hello
 
     @pytest.fixture
     def hello(request):
-        name = request.config.option.name
+        name = request.config.getoption('name')
 
         def _hello(name=None):
             if not name:
-                name = request.config.option.name
+                name = request.config.getoption('name')
             return "Hello {name}!".format(name=name)
 
         return _hello