vim-patch:9.1.0150: Several minor 'winfixbuf' issues

Problem:  several minor 'winfixbuf' issues exist, mostly relating to the
          quickfix list
Solution: address them and adjust tests. Retab and reflow a few things too.
          (Sean Dewar)

Things touched include:

- Replace the semsgs with gettext'd emsgs.

- Handle window switching in ex_listdo properly, so curbuf and curwin
  are kept in-sync and trigger autocommands; handle those properly.

- Don't change the list entry index in qf_jump_edit_buffer if we fail
  due to 'wfb' (achieved by returning FAIL; QF_ABORT should only be used
  if the list was changed).

- Make qf_jump_edit_buffer actually switch to prevwin when using `:cXX`
  commands **outside** of the list window if 'wfb' is set in curwin.
  Handle autocommands properly in case they mess with the list.

  NOTE: previously, it seemed to split if 'wfb' was set, but do nothing
  and fail if prevwin is *valid*. This behaviour seemed strange, and maybe
  unintentional? Now it aligns more with what's described for the `:cXX`
  commands in the original PR description when used outside a list window,
  I think.

- In both functions, only consider prevwin if 'wfb' isn't set for it;
  fallback to splitting otherwise.

- Use win_split to split. Not sure if there was a specific reason for
  using ex_splitview. win_split is simpler and respects modifiers like
  :vertical that may have been used. Plus, its return value can be checked
  for setting opened_window in qf code (technically win_split_ins autocmds
  could immediately close it or change windows, in which the qf code might
  close some other window on failure; it's already the case elsewhere,
  though).

closes: vim/vim#14142

4bb505e28c

Co-authored-by: Sean Dewar <6256228+seandewar@users.noreply.github.com>

src/nvim/ex_cmds2.c

@@ -447,21 +447,24 @@ void ex_listdo(exarg_T *eap)
   if (curwin->w_p_wfb) {
     if ((eap->cmdidx == CMD_ldo || eap->cmdidx == CMD_lfdo) && !eap->forceit) {
       // Disallow :ldo if 'winfixbuf' is applied
-      semsg("%s", e_winfixbuf_cannot_go_to_buffer);
+      emsg(_(e_winfixbuf_cannot_go_to_buffer));
       return;
     }
 
-    if (win_valid(prevwin)) {
-      // Change the current window to another because 'winfixbuf' is enabled
-      curwin = prevwin;
-    } else {
+    if (win_valid(prevwin) && !prevwin->w_p_wfb) {
+      // 'winfixbuf' is set; attempt to change to a window without it.
+      win_goto(prevwin);
+    }
+    if (curwin->w_p_wfb) {
       // Split the window, which will be 'nowinfixbuf', and set curwin to that
-      exarg_T new_eap = {
-        .cmdidx = CMD_split,
-        .cmd = "split",
-        .arg = "",
-      };
-      ex_splitview(&new_eap);
+      win_split(0, 0);
+
+      if (curwin->w_p_wfb) {
+        // Autocommands set 'winfixbuf' or sent us to another window
+        // with it set. Give up.
+        emsg(_(e_winfixbuf_cannot_go_to_buffer));
+        return;
+      }
     }
   }