fix(shell): on Windows :make does not echo #22728

Problem:
On Windows, :make does not display the output of the program it runs.
The cause is the default 'shellpipe'.  On Linux, nvim uses `tee` to redirect the
output to both stdout and the error file.  In Windows, for both cmd.exe and
powershell, the output is only redirected to the error file.

Solution:
- On Windows, change the 'shellpipe' default to "2>&1| tee".
    - Nvim includes `tee` in its Windows package.
- Document recommended defaults for powershell.

Fixes #12910

test/old/testdir/test_shell.vim

@@ -22,7 +22,7 @@ func Test_shell_options()
           \ ['tcsh', '-c', '|& tee', '', '>&', '', '']]
   endif
   if has('win32')
-    let shells += [['cmd', '/s /c', '>%s 2>&1', '', '>%s 2>&1', '', '"']]
+    let shells += [['cmd', '/s /c', '2>&1| tee', '', '>%s 2>&1', '', '"']]
   endif
 
   " start a new Vim instance with 'shell' set to each of the supported shells