patch 8.0.1715: terminal buffer can be 1 more than 'terminalscroll' lines

Problem:    Terminal buffer can be 1 more than 'terminalscroll' lines.
Solution:   Change > to >=.

src/terminal.c

@@ -2518,7 +2518,7 @@ handle_pushline(int cols, const VTermScreenCell *cells, void *user)
 
     /* If the number of lines that are stored goes over 'termscrollback' then
      * delete the first 10%. */
-    if (term->tl_scrollback.ga_len > p_tlsl)
+    if (term->tl_scrollback.ga_len >= p_tlsl)
     {
 	int	todo = p_tlsl / 10;
 	int	i;

src/version.c

@@ -762,6 +762,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1715,
 /**/
     1714,
 /**/