patch 9.1.0206: unused display_text_first boolean var in win_line()

patch 9.1.0206: unused display_text_first boolean var in win_line()

Problem:  unused display_text_first boolean var in win_line()
Solution: Remove unused display_text_first boolean variable
          (Dylan Thacker-Smith)

The only place it is used, uses its initial constant value, then the
following conditionally values set to the variable are unused.

Specifically, it was commit 234c3fab28c14846b962c90097496b27ee1b4df8
that changed the use of display_text_first such that it doesn't have any
effect.

closes: #14305

Signed-off-by: Dylan Thacker-Smith <dylan.ah.smith@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>