patch 8.1.1205: a BufReadPre autocommand may cause the cursor to move

Problem:    A BufReadPre autocommand may cause the cursor to move.
Solution:   Restore the cursor position after executing the autocommand,
            unless the autocommand moved it. (Christian Brabandt,
            closes #4302, closes #4294)
diff --git a/src/proto/window.pro b/src/proto/window.pro
index 5da322e..b4ad98a 100644
--- a/src/proto/window.pro
+++ b/src/proto/window.pro
@@ -70,6 +70,7 @@
 int min_rows(void);
 int only_one_window(void);
 void check_lnums(int do_curwin);
+void reset_lnums(void);
 void make_snapshot(int idx);
 void restore_snapshot(int idx, int close_curwin);
 int switch_win(win_T **save_curwin, tabpage_T **save_curtab, win_T *win, tabpage_T *tp, int no_display);