qtconsole: strip newline on text copy (fixes #6234)

IPython's inputsplitter inserts newline at the end of string passed to
it. So, if user didn't select newline before copying, we must strip it.

IPython/qt/console/frontend_widget.py

@@ -215,7 +215,10 b' class FrontendWidget(HistoryConsoleWidget, BaseFrontendMixin):'
         elif self._control.hasFocus():
             text = self._control.textCursor().selection().toPlainText()
             if text:
+                was_newline = text[-1] == '\n'
                 text = self._prompt_transformer.transform_cell(text)
+                if not was_newline: # user don't need newline
+                    text = text[:-1]
                 QtGui.QApplication.clipboard().setText(text)
         else:
             self.log.debug("frontend widget : unknown copy target")