🔥 Remove _typing.py file

It was only used to import the `get_args` and `get_origin` methods, but we can
import them from `typing_extensions` directly.

pyproject.toml

@@ -125,9 +125,6 @@ source = [
     "tests",
     "typer"
 ]
-omit = [
-    "typer/_typing.py"
-]
 context = '${CONTEXT}'
 
 [tool.coverage.report]
@@ -189,9 +186,6 @@ ignore = [
 # Loop control variable `x` not used within loop body
 "docs_src/using_click/tutorial001.py" = ["B007"]
 
-# TODO: refactor _typing.py, remove unnecessary code
-"typer/_typing.py" = ["UP036", "F822"]
-
 [tool.ruff.lint.isort]
 known-third-party = ["typer", "click"]
 # For docs_src/subcommands/tutorial003/