fix(widgets) remove the prototype of some unimplemented functions

src/extra/widgets/keyboard/lv_keyboard.h

@@ -109,13 +109,6 @@ lv_obj_t * lv_keyboard_get_textarea(const lv_obj_t * kb);
  */
 lv_keyboard_mode_t lv_keyboard_get_mode(const lv_obj_t * kb);
 
-/**
- * Get the current cursor manage mode.
- * @param kb pointer to a Keyboard object
- * @return true: show cursor on the current text area, false: hide cursor
- */
-bool lv_keyboard_get_cursor_manage(const lv_obj_t * kb);
-
 /**
  * Get the current map of a keyboard
  * @param kb pointer to a keyboard object

src/extra/widgets/spinbox/lv_spinbox.h

@@ -99,13 +99,6 @@ void lv_spinbox_set_step(lv_obj_t * obj, uint32_t step);
  */
 void lv_spinbox_set_range(lv_obj_t * obj, int32_t range_min, int32_t range_max);
 
-/**
- * Set spinbox left padding in digits count (added between sign and first digit)
- * @param spinbox pointer to spinbox
- * @param cb Callback function called on value change event
- */
-void lv_spinbox_set_padding_left(lv_obj_t * obj, uint8_t padding);
-
 /*=====================
  * Getter functions
  *====================*/

src/widgets/lv_arc.h

@@ -154,13 +154,6 @@ void lv_arc_set_range(lv_obj_t * arc, int16_t min, int16_t max);
  */
 void lv_arc_set_chg_rate(lv_obj_t * arc, uint16_t threshold);
 
-/**
- * Set whether the arc is adjustable.
- * @param arc pointer to a arc object
- * @param adjustable whether the arc has a knob that can be dragged
- */
-void lv_arc_set_adjustable(lv_obj_t * arc, bool adjustable);
-
 /*=====================
  * Getter functions
  *====================*/
@@ -221,13 +214,6 @@ int16_t lv_arc_get_max_value(const lv_obj_t * obj);
  */
 lv_arc_type_t lv_arc_get_type(const lv_obj_t * obj);
 
-/**
- * Get whether the arc is adjustable.
- * @param arc pointer to a arc object
- * @return whether the arc has a knob that can be dragged
- */
-bool lv_arc_get_adjustable(lv_obj_t * obj);
-
 /*=====================
  * Other functions
  *====================*/