patch 9.1.0831: 'findexpr' can't be used as lambad or Funcref

Problem:  'findexpr' can't be used for lambads
          (Justin Keyes)
Solution: Replace the findexpr option with the findfunc option
          (Yegappan Lakshmanan)

related: #15905
closes: #15976

Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/proto/option.pro b/src/proto/option.pro
index fce9199..83f32aa 100644
--- a/src/proto/option.pro
+++ b/src/proto/option.pro
@@ -120,7 +120,7 @@
 char_u *get_option_fullname(int opt_idx);
 opt_did_set_cb_T get_option_did_set_cb(int opt_idx);
 char_u *get_equalprg(void);
-char_u *get_findexpr(void);
+char_u *get_findfunc(void);
 void win_copy_options(win_T *wp_from, win_T *wp_to);
 void after_copy_winopt(win_T *wp);
 void copy_winopt(winopt_T *from, winopt_T *to);