patch 8.2.2198: ml_get error when resizing window and using text property

Problem:    ml_get error when resizing window and using text property.
Solution:   Validate botline of the right window. (closes #7528)
diff --git a/src/proto/move.pro b/src/proto/move.pro
index 8efecb9..d78623a 100644
--- a/src/proto/move.pro
+++ b/src/proto/move.pro
@@ -13,6 +13,7 @@
 void changed_line_abv_curs(void);
 void changed_line_abv_curs_win(win_T *wp);
 void validate_botline(void);
+void validate_botline_win(win_T *wp);
 void invalidate_botline(void);
 void invalidate_botline_win(win_T *wp);
 void approximate_botline_win(win_T *wp);