Gui: Add support for hints in status bar

src/Mod/Sketcher/Gui/DrawSketchControllableHandler.h

@@ -160,7 +160,10 @@ private:
     bool onModeChanged() override
     {
         DrawSketchHandler::resetPositionText();
+        DrawSketchHandler::updateHint();
+
         toolWidgetManager.onHandlerModeChanged();
+
         if (DSDefaultHandler::onModeChanged()) {
             // If onModeChanged returns false, then the handler has been purged.
             toolWidgetManager.afterHandlerModeChanged();

src/Mod/Sketcher/Gui/DrawSketchHandlerLineSet.h

@@ -96,6 +96,17 @@ public:
         SNAP_MODE_45Degree
     };
 
+    std::list<Gui::InputHint> getToolHints() const override
+    {
+        using UserInput = Gui::InputHint::UserInput;
+
+        return {
+            {QWidget::tr("%1 change mode"), {UserInput::KeyM}},
+            {QWidget::tr("%1 start drawing"), {UserInput::MouseLeft}},
+            {QWidget::tr("%1 stop drawing"), {UserInput::MouseRight}},
+        };
+    }
+
     void registerPressedKey(bool pressed, int key) override
     {
         if (Mode == STATUS_SEEK_Second && key == SoKeyboardEvent::M && pressed

src/Mod/Sketcher/Gui/DrawSketchHandlerPolygon.h

@@ -74,6 +74,29 @@ public:
     {}
     ~DrawSketchHandlerPolygon() override = default;
 
+    std::list<Gui::InputHint> getToolHints() const override
+    {
+        using UserInput = Gui::InputHint::UserInput;
+
+        switch (state()) {
+            case SelectMode::SeekFirst:
+                return {
+                    {QWidget::tr("%1 pick polygon center"), {UserInput::MouseLeft}},
+                    {QWidget::tr("%1/%2 increase / decrease number of sides"),
+                     {UserInput::KeyU, UserInput::KeyJ}},
+                };
+            case SelectMode::SeekSecond:
+                return {
+                    {QWidget::tr("%1 pick rotation and size"), {UserInput::MouseMove}},
+                    {QWidget::tr("%1 confirm"), {UserInput::MouseLeft}},
+                    {QWidget::tr("%1/%2 increase / decrease number of sides"),
+                     {UserInput::KeyU, UserInput::KeyJ}},
+                };
+            default:
+                return {};
+        }
+    }
+
 private:
     void updateDataAndDrawToPosition(Base::Vector2d onSketchPos) override
     {