patch 8.2.4969: changing text in Visual mode may cause invalid memory access

Problem:    Changing text in Visual mode may cause invalid memory access.
Solution:   Check the Visual position after making a change.
diff --git a/src/proto/misc2.pro b/src/proto/misc2.pro
index fe0a4fb..2728ffe 100644
--- a/src/proto/misc2.pro
+++ b/src/proto/misc2.pro
@@ -17,6 +17,7 @@
 void check_cursor_col(void);
 void check_cursor_col_win(win_T *win);
 void check_cursor(void);
+void check_visual_pos(void);
 void adjust_cursor_col(void);
 int leftcol_changed(void);
 int copy_option_part(char_u **option, char_u *buf, int maxlen, char *sep_chars);