patch 9.1.0014: incorrect use of W_WINROW in edit.c

Problem:  incorrect use of W_WINROW in edit.c
Solution: compare against curwin->w_height instead

Remove incorrect use of W_WINROW

In structs.h it is mentioned that w_wrow is relative to w_winrow, so
using W_WINROW doesn't make sense when comparing with window height.

This change won't lead to any observable behavior change:

The condition intends to check if there are 'scrolloff' lines between
the current cursor when the bottom of the window. When W_WINROW(curwin)
is added to curwin->w_height - 1 - get_scrolloff_value(), the condition
is instead satisfied when the cursor is on some screen line below that
position. However,
- If 'scrolloff' is smaller than half the window height, this condition
  can only be satisfied when W_WINROW(curwin) == 0. And if it is not
  satisfied, update_topline() does the actual scrolling.
- If 'scrolloff' is larger than half the window height, update_topline()
  will put the cursor at the center of the window soon afterwards
  anyway, because set_topline() now unsets VALID_TOPLINE flag starting
  from https://github.com/vim/vim-history/commit/7db7bb45b0f919ff0615d463ebd4fde881c69d1f.

To put it in another way, https://github.com/vim/vim-history/commit/7db7bb45b0f919ff0615d463ebd4fde881c69d1f
makes the update_topline() just below correct the mistakes made in this
block, so this incorrect use of W_WINROW() no longer affects observable
behavior.

closes: #12331

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/edit.c b/src/edit.c
index f89d43e..cb6ae7e 100644
--- a/src/edit.c
+++ b/src/edit.c
@@ -525,8 +525,8 @@
 #else
 		(int)curwin->w_wcol < mincol - curbuf->b_p_ts
 #endif
-		    && curwin->w_wrow == W_WINROW(curwin)
-				 + curwin->w_height - 1 - get_scrolloff_value()
+		    && curwin->w_wrow ==
+				   curwin->w_height - 1 - get_scrolloff_value()
 		    && (curwin->w_cursor.lnum != curwin->w_topline
 #ifdef FEAT_DIFF
 			|| curwin->w_topfill > 0