patch 9.1.0294: Text height function does not respect it's argument

Problem:  plines_m_win() does not take into account it's "limit_winheight"
          argument for filler lines below the last line of the buffer.
          (after v9.1.0280)
Solution: Check window height when "limit_winheight" is TRUE.
          (Luuk van Baal)

closes: #14449

Signed-off-by: Luuk van Baal <luukvbaal@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    294,
 /**/
     293,
 /**/