LibGUI: Remove declarations for non-existent methods

Userland/Libraries/LibGUI/AbstractSlider.h

@@ -56,8 +56,6 @@ protected:
     explicit AbstractSlider(Orientation = Orientation::Vertical);
 
 private:
-    void set_knob_hovered(bool);
-
     int m_value { 0 };
     int m_min { 0 };
     int m_max { 0 };

Userland/Libraries/LibGUI/MultiView.h

@@ -20,8 +20,6 @@ class MultiView final : public GUI::StackWidget {
 public:
     virtual ~MultiView() override = default;
 
-    void refresh();
-
     Function<void()> on_selection_change;
     Function<void(ModelIndex const&)> on_activation;
     Function<void(ModelIndex const&)> on_selection;

Userland/Libraries/LibGUI/TextEditor.h

@@ -306,7 +306,6 @@ private:
     virtual void automatic_scrolling_timer_did_fire() override;
 
     void create_actions();
-    void paint_ruler(Painter&);
     void update_content_size();
     int fixed_glyph_width() const;
 

Userland/Libraries/LibGUI/VimEditingEngine.h

@@ -122,7 +122,6 @@ private:
     void calculate_document_range(TextEditor&);
     void calculate_line_range(TextEditor&, bool normalize_for_position);
     void calculate_word_range(VimCursor&, int amount, bool normalize_for_position);
-    void calculate_WORD_range(VimCursor&, int amount, bool normalize_for_position);
     void calculate_character_range(VimCursor&, int amount, bool normalize_for_position);
     void calculate_find_range(VimCursor&, int amount);