Fix compile error due to -Wstrict-prototypes

Author: Luflosi

kitty/state.h

@@ -203,7 +203,7 @@ OSWindow* current_os_window(void);
 void os_window_regions(OSWindow*, Region *main, Region *tab_bar);
 bool drag_scroll(Window *, OSWindow*);
 void setup_scroll(OSWindow *os_window);
-void before_render();
+void before_render(void);
 void after_render(OSWindow *os_window, double pixels);
 void draw_borders(ssize_t vao_idx, unsigned int num_border_rects, BorderRect *rect_buf, bool rect_data_is_dirty, uint32_t viewport_width, uint32_t viewport_height, color_type, unsigned int, OSWindow *w);
 ssize_t create_cell_vao(void);