prefer the full name of powershell

Author: frostming

docs/html/user_guide.rst

@@ -745,7 +745,7 @@ To setup for fish::
 
 To setup for powershell::
 
-   python -m pip completion --posh | Out-File -Encoding default -Append $PROFILE
+   python -m pip completion --powershell | Out-File -Encoding default -Append $PROFILE
 
 Alternatively, you can use the result of the ``completion`` command directly
 with the eval function of your shell, e.g. by adding the following to your

src/pip/_internal/commands/completion.py

@@ -48,7 +48,7 @@
         end
         complete -fa "(__fish_complete_pip)" -c {prog}
     """,
-    'posh': """
+    'powershell': """
         if ((Test-Path Function:\\TabExpansion) -and -not `
             (Test-Path Function:\\_pip_completeBackup)) {{
             Rename-Item Function:\\TabExpansion _pip_completeBackup
@@ -99,9 +99,9 @@ def add_options(self):
             dest='shell',
             help='Emit completion code for fish')
         self.cmd_opts.add_option(
-            '--posh', '-p',
+            '--powershell', '-p',
             action='store_const',
-            const='posh',
+            const='powershell',
             dest='shell',
             help='Emit completion code for powershell')
 

tests/functional/test_completion.py

@@ -34,7 +34,7 @@
              PIP_AUTO_COMPLETE=1 $words[1] 2>/dev/null ))
 }
 compctl -K _pip_completion pip"""),
-    ('posh', """\
+    ('powershell', """\
 if ((Test-Path Function:\\TabExpansion) -and -not `
     (Test-Path Function:\\_pip_completeBackup)) {
     Rename-Item Function:\\TabExpansion _pip_completeBackup
@@ -129,7 +129,7 @@ def test_completion_alone(autocomplete_script):
     Test getting completion for none shell, just pip completion
     """
     result = autocomplete_script.pip('completion', allow_stderr_error=True)
-    assert 'ERROR: You must pass --bash or --fish or --posh or --zsh' \
+    assert 'ERROR: You must pass --bash or --fish or --powershell or --zsh' \
            in result.stderr, 'completion alone failed -- ' + result.stderr
 
 
@@ -325,7 +325,7 @@ def test_completion_path_after_option(autocomplete, data):
     )
 
 
-@pytest.mark.parametrize('flag', ['--bash', '--zsh', '--fish', '--posh'])
+@pytest.mark.parametrize('flag', ['--bash', '--zsh', '--fish', '--powershell'])
 def test_completion_uses_same_executable_name(
     autocomplete_script, flag, deprecated_python
 ):