[Core] Remove matrix_is_modified() and debounce_is_active() (#15349)

keyboards/redscarf_iiplus/verd/matrix.c

@@ -94,13 +94,6 @@ uint8_t matrix_cols(void) {
     return MATRIX_COLS;
 }
 
-//Deprecated.
-bool matrix_is_modified(void)
-{
-    if (debounce_active()) return false;
-    return true;
-}
-
 inline
 bool matrix_is_on(uint8_t row, uint8_t col)
 {