patch 9.1.0572: cannot specify tab page closing behaviour

Problem:  cannot specify tab page closing behaviour
          (Gianluca Pacchiella)
Solution: Add the 'tabclose' option (LemonBoy).

fixes: #5967
closes: #15204

Signed-off-by: LemonBoy <thatlemon@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/proto/option.pro b/src/proto/option.pro
index 69463d4..1659131 100644
--- a/src/proto/option.pro
+++ b/src/proto/option.pro
@@ -69,6 +69,7 @@
 char *did_set_smoothscroll(optset_T *args);
 char *did_set_spell(optset_T *args);
 char *did_set_swapfile(optset_T *args);
+char *did_set_tabclose(optset_T *args);
 char *did_set_termguicolors(optset_T *args);
 char *did_set_terse(optset_T *args);
 char *did_set_textauto(optset_T *args);
diff --git a/src/proto/optionstr.pro b/src/proto/optionstr.pro
index 340ffc4..39c40f3 100644
--- a/src/proto/optionstr.pro
+++ b/src/proto/optionstr.pro
@@ -156,6 +156,7 @@
 int expand_set_swapsync(optexpand_T *args, int *numMatches, char_u ***matches);
 char *did_set_switchbuf(optset_T *args);
 int expand_set_switchbuf(optexpand_T *args, int *numMatches, char_u ***matches);
+int expand_set_tabclose(optexpand_T *args, int *numMatches, char_u ***matches);
 char *did_set_tabline(optset_T *args);
 char *did_set_tagcase(optset_T *args);
 int expand_set_tagcase(optexpand_T *args, int *numMatches, char_u ***matches);