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

src/nvim/options.lua

@@ -2026,7 +2026,7 @@ return {
       varname='p_sp',
       defaults={
         condition='MSWIN',
-        if_true=">%s 2>&1",
+        if_true="2>&1| tee",
         if_false="| tee",
       }
     },