patch 8.2.3941: SIGTSTP is not handled

Problem:    SIGTSTP is not handled.
Solution:   Handle SIGTSTP like pressing CTRL-Z. (closes #9422)
diff --git a/src/ex_docmd.c b/src/ex_docmd.c
index 8f4f4ae..12824a9 100644
--- a/src/ex_docmd.c
+++ b/src/ex_docmd.c
@@ -109,7 +109,6 @@
 # define ex_pedit		ex_ni
 #endif
 static void	ex_hide(exarg_T *eap);
-static void	ex_stop(exarg_T *eap);
 static void	ex_exit(exarg_T *eap);
 static void	ex_print(exarg_T *eap);
 #ifdef FEAT_BYTEOFF
@@ -6200,7 +6199,7 @@
 /*
  * ":stop" and ":suspend": Suspend Vim.
  */
-    static void
+    void
 ex_stop(exarg_T *eap)
 {
     /*