Fix pylint 2.0 useless-return cases

See https://github.com/PyCQA/pylint/issues/2300

qutebrowser/browser/webengine/webenginetab.py

@@ -1086,10 +1086,10 @@ class WebEngineTab(browsertab.AbstractTab):
         # percent encoded content is 2 megabytes minus 30 bytes.
         self._widget.setHtml(html, base_url)
 
-    def networkaccessmanager(self):
+    def networkaccessmanager(self):  # pylint: disable=useless-return
         return None
 
-    def user_agent(self):
+    def user_agent(self):  # pylint: disable=useless-return
         return None
 
     def clear_ssl_errors(self):

qutebrowser/misc/miscwidgets.py

@@ -246,7 +246,7 @@ class WrapperLayout(QLayout):
     def sizeHint(self):
         return self._widget.sizeHint()
 
-    def itemAt(self, _index):
+    def itemAt(self, _index):  # pylint: disable=useless-return
         return None
 
     def takeAt(self, _index):
@@ -287,7 +287,7 @@ class PseudoLayout(QLayout):
     def count(self):
         return 0
 
-    def itemAt(self, _pos):
+    def itemAt(self, _pos):  # pylint: disable=useless-return
         return None
 
     def widget(self):

qutebrowser/misc/utilcmds.py

@@ -365,7 +365,7 @@ def window_only(current_win_id):
 @cmdutils.register()
 def nop():
     """Do nothing."""
-    return
+    pass
 
 
 @cmdutils.register()

tests/end2end/fixtures/test_quteprocess.py

@@ -68,7 +68,7 @@ class FakeNode:
     def __init__(self, call):
         self.rep_call = call
 
-    def get_closest_marker(self, _name):
+    def get_closest_marker(self, _name):  # pylint: disable=useless-return
         return None
 
 

tests/helpers/stubs.py

@@ -44,7 +44,7 @@ class FakeNetworkCache(QAbstractNetworkCache):
     def cacheSize(self):
         return 0
 
-    def data(self, _url):
+    def data(self, _url):  # pylint: disable=useless-return
         return None
 
     def insert(self, _dev):
@@ -53,7 +53,7 @@ class FakeNetworkCache(QAbstractNetworkCache):
     def metaData(self, _url):
         return QNetworkCacheMetaData()
 
-    def prepare(self, _metadata):
+    def prepare(self, _metadata):  # pylint: disable=useless-return
         return None
 
     def remove(self, _url):

tests/unit/utils/test_qtutils.py

@@ -575,7 +575,7 @@ class FailingQIODevice(QIODevice):
         self.setErrorString("Writing failed")
         return -1
 
-    def read(self, _maxsize):
+    def read(self, _maxsize):  # pylint: disable=useless-return
         """Simulate failed read."""
         self.setErrorString("Reading failed")
         return None

tests/unit/utils/test_utils.py

@@ -410,11 +410,11 @@ class GotException(Exception):
 
 
 def excepthook(_exc, _val, _tb):
-    return
+    pass
 
 
 def excepthook_2(_exc, _val, _tb):
-    return
+    pass
 
 
 class TestDisabledExcepthook: