refactor: merge bufIsChangedNotTerm into bufIsChanged

... As the latter just calls the former.

src/ex_cmds.c

@@ -1563,13 +1563,8 @@ void do_shell(
     msg_putchar('\n'); // may shift screen one line up
 
   // warning message before calling the shell
-  if (p_warn && !autocmd_busy && msg_silent == 0)
-    FOR_ALL_BUFFERS(buf)
-  if (bufIsChangedNotTerm(buf))
-  {
+  if (p_warn && !autocmd_busy && msg_silent == 0 && anyBufIsChanged())
     msg_puts(_("[No write since last change]\n"));
-    break;
-  }
 
   // This windgoto is required for when the '\n' resulted in a "delete line
   // 1" command to the terminal.

src/proto/undo.pro

@@ -26,7 +26,6 @@ void u_undoline(void);
 void u_blockfree(buf_T *buf);
 int bufIsChanged(buf_T *buf);
 int anyBufIsChanged(void);
-int bufIsChangedNotTerm(buf_T *buf);
 int curbufIsChanged(void);
 void u_eval_tree(u_header_T *first_uhp, list_T *list);
 /* vim: set ft=c : */

src/undo.c

@@ -3148,13 +3148,13 @@ void u_blockfree(buf_T *buf)
  * Check if the 'modified' flag is set, or 'ff' has changed (only need to
  * check the first character, because it can only be "dos", "unix" or "mac").
  * "nofile" and "scratch" type buffers are considered to always be unchanged.
- * Also considers a buffer changed when a terminal window contains a running
- * job.
  */
 int bufIsChanged(buf_T *buf)
 {
 
-  return bufIsChangedNotTerm(buf);
+  // In a "prompt" buffer we do respect 'modified', so that we can control
+  // closing the window by setting or resetting that option.
+  return (!bt_dontwrite(buf) || bt_prompt(buf)) && (buf->b_changed || file_ff_differs(buf, TRUE));
 }
 
 /*
@@ -3170,16 +3170,6 @@ int anyBufIsChanged(void)
   return FALSE;
 }
 
-/*
- * Like bufIsChanged() but ignoring a terminal window.
- */
-int bufIsChangedNotTerm(buf_T *buf)
-{
-  // In a "prompt" buffer we do respect 'modified', so that we can control
-  // closing the window by setting or resetting that option.
-  return (!bt_dontwrite(buf) || bt_prompt(buf)) && (buf->b_changed || file_ff_differs(buf, TRUE));
-}
-
 int curbufIsChanged(void)
 {
   return bufIsChanged(curbuf);