Add backslash to the list of word separator.

Task-number: QTBUG-40384
Change-Id: I16ae1432f3bdd7e577593fc43336bf29c735a66b
Reviewed-by: Konstantin Ritt <ritt.ks@gmail.com>
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>

src/gui/text/qtextengine.cpp

@@ -2449,6 +2449,7 @@ bool QTextEngine::atWordSeparator(int position) const
     case '`':
     case '~':
     case '|':
+    case '\\':
         return true;
     default:
         break;