fix type lifting with 'Union' types

Now that we have real types for setfont, I tried to lift there in a test.
It didn't work, because we didn't explicitly import 'Union' into the type
lifter function's namespace, so we ended up with:

    2024-04-27 16:31:01,582 libqtile loop.py:_handle_exception():L62  Exception in event loop:
    Traceback (most recent call last):
      File "/home/tycho/packages/qtile/libqtile/ipc.py", line 235, in _server_callback
        rep = self.handler(req)
      File "/home/tycho/packages/qtile/libqtile/command/interface.py", line 424, in call
        args, kwargs = lift_args(cmd, args, kwargs)
      File "/home/tycho/packages/qtile/libqtile/command/interface.py", line 367, in lift_args
        params = typing.get_type_hints(cmd, globalns=globals())
      File "/usr/lib/python3.10/typing.py", line 1871, in get_type_hints
        value = _eval_type(value, globalns, localns)
      File "/usr/lib/python3.10/typing.py", line 327, in _eval_type
        return t._evaluate(globalns, localns, recursive_guard)
      File "/usr/lib/python3.10/typing.py", line 694, in _evaluate
        eval(self.__forward_code__, globalns, localns),
      File "<string>", line 1, in <module>
    NameError: name 'Union' is not defined

this is the unfortunate reality that I described in the original lifting
commit: we need to have all these types aligned and available in the local
namespace in order to make this work. So, let's make this true for Union.

Signed-off-by: Tycho Andersen <tycho@tycho.pizza>

libqtile/command/interface.py

@@ -28,7 +28,7 @@
 import types
 import typing
 from abc import ABCMeta, abstractmethod
-from typing import TYPE_CHECKING, Any, Literal, get_args, get_origin
+from typing import TYPE_CHECKING, Any, Literal, Union, get_args, get_origin
 
 from libqtile import ipc
 from libqtile.command.base import CommandError, CommandException, CommandObject, SelectError
@@ -309,7 +309,7 @@ def lift_args(cmd, args, kwargs):
 
     def lift_arg(typ, arg):
         # for stuff like int | None, allow either
-        if get_origin(typ) in [types.UnionType, typing.Union]:
+        if get_origin(typ) in [types.UnionType, Union]:
             for t in get_args(typ):
                 if t == types.NoneType:
                     # special case None? I don't know what this looks like

test/test_command.py

@@ -68,6 +68,7 @@ class CallConfig(Config):
             bottom=libqtile.bar.Bar(
                 [
                     libqtile.widget.GroupBox(),
+                    libqtile.widget.TextBox(),
                 ],
                 20,
             ),
@@ -110,6 +111,12 @@ def test_param_hoisting(manager):
 
     cmd_client.call("hide_show_bar", position="top", lifted=True)
 
+    # 'zomg' is not a valid font size
+    with pytest.raises(IPCError):
+        cmd_client.navigate("widget", "textbox").call("set_font", fontsize="zomg", lifted=True)
+
+    cmd_client.navigate("widget", "textbox").call("set_font", fontsize=12, lifted=True)
+
 
 class FakeCommandObject(CommandObject):
     @staticmethod