Document hint lastChild() hack

THANKS

@@ -25,9 +25,10 @@ valuable ones:
     - chelmuth
     - quark
     - Bleeding Fingers
+    - artyom.stv
 
 Thanks to these people for helpful bits and pieces in the Qt bugtracker and IRC
-channel:
+channels:
     - Allan Sandfeld Jensen
     - bachewii
     - Vitaliy Filippov

qutebrowser/browser/hints.py

@@ -266,6 +266,11 @@ class HintManager(QObject):
         css = self.HINT_CSS.format(left=rect.x(), top=rect.y(),
                                    config=config.instance)
         doc = self._frame.documentElement()
+        # It seems impossible to create an empty QWebElement for which isNull()
+        # is false so we can work with it.
+        # As a workaround, we use appendInside() with markup as argument, and
+        # then use lastChild() to get a reference to it.
+        # See: http://stackoverflow.com/q/7364852/2085149
         doc.appendInside('<span class="qutehint" style="{}">{}</span>'.format(
                          css, string))
         return doc.lastChild()