drop python.exe extension on windows on shebang

pre_commit/commands/install_uninstall.py

@@ -55,7 +55,7 @@ def is_our_script(filename: str) -> bool:
 
 def shebang() -> str:
     if sys.platform == 'win32':
-        py = SYS_EXE
+        py, _ = os.path.splitext(SYS_EXE)
     else:
         exe_choices = [
             f'python{sys.version_info[0]}.{sys.version_info[1]}',

tests/commands/install_uninstall_test.py

@@ -56,8 +56,13 @@ def patch_sys_exe(exe):
 
 
 def test_shebang_windows():
+    with patch_platform('win32'), patch_sys_exe('python'):
+        assert shebang() == '#!/usr/bin/env python'
+
+
+def test_shebang_windows_drop_ext():
     with patch_platform('win32'), patch_sys_exe('python.exe'):
-        assert shebang() == '#!/usr/bin/env python.exe'
+        assert shebang() == '#!/usr/bin/env python'
 
 
 def test_shebang_posix_not_on_path():