refactor(misc1): move out autocmd related functions

src/nvim/buffer_defs.h

@@ -1116,12 +1116,6 @@ typedef struct {
   pos_T w_cursor_corr;  // corrected cursor position
 } pos_save_T;
 
-// Struct passed to get_v_event() and restore_v_event().
-typedef struct {
-  bool sve_did_save;
-  hashtab_T sve_hashtab;
-} save_v_event_T;
-
 /// Indices into vimmenu_T->strings[] and vimmenu_T->noremap[] for each mode
 /// \addtogroup MENU_INDEX
 /// @{