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/functional/helpers.lua

@@ -553,16 +553,18 @@ function module.set_shell_powershell(fake)
     assert(found)
   end
   local shell = found and (is_os('win') and 'powershell' or 'pwsh') or module.testprg('pwsh-test')
-  local set_encoding = '[Console]::InputEncoding=[Console]::OutputEncoding=[System.Text.UTF8Encoding]::new();'
-  local cmd = set_encoding..'Remove-Item -Force '..table.concat(is_os('win')
+  local cmd = 'Remove-Item -Force '..table.concat(is_os('win')
     and {'alias:cat', 'alias:echo', 'alias:sleep', 'alias:sort'}
     or  {'alias:echo'}, ',')..';'
   module.exec([[
     let &shell = ']]..shell..[['
     set shellquote= shellxquote=
-    let &shellcmdflag = '-NoLogo -NoProfile -ExecutionPolicy RemoteSigned -Command ]]..cmd..[['
-    let &shellpipe = '2>&1 | Out-File -Encoding UTF8 %s; exit $LastExitCode'
-    let &shellredir = '2>&1 | Out-File -Encoding UTF8 %s; exit $LastExitCode'
+    let &shellcmdflag = '-NoLogo -NoProfile -ExecutionPolicy RemoteSigned -Command '
+    let &shellcmdflag .= '[Console]::InputEncoding=[Console]::OutputEncoding=[System.Text.UTF8Encoding]::new();'
+    let &shellcmdflag .= '$PSDefaultParameterValues[''Out-File:Encoding'']=''utf8'';'
+    let &shellcmdflag .= ']]..cmd..[['
+    let &shellredir = '2>&1 | %%{ "$_" } | Out-File %s; exit $LastExitCode'
+    let &shellpipe  = '2>&1 | %%{ "$_" } | Tee-Object %s; exit $LastExitCode'
   ]])
   return found
 end