Core: Remove the now-unused ICore::optionsDialogRequested() signal

Change-Id: I5b712c8f01170d406b2a1e5cb969ff2e4ffe16d4
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/coreplugin/icore.cpp

@@ -360,8 +360,6 @@ bool ICore::showOptionsDialog(const Id page, QWidget *parent)
     // Make sure all wizards are there when the user might access the keyboard shortcuts:
     (void) IWizardFactory::allWizardFactories();
 
-    emit m_instance->optionsDialogRequested();
-
     if (!parent)
         parent = dialogParent();
     SettingsDialog *dialog = SettingsDialog::getSettingsDialog(parent, page);

src/plugins/coreplugin/icore.h

@@ -144,7 +144,6 @@ signals:
     void coreOpened();
     void newItemDialogStateChanged();
     void saveSettingsRequested();
-    void optionsDialogRequested();
     void coreAboutToClose();
     void contextAboutToChange(const QList<Core::IContext *> &context);
     void contextChanged(const Core::Context &context);