chore(mypy): Remove unused ignore_missing_imports overrides

why: Bundled extension modules are now provided by PyPI packages.
what:
- Remove mypy overrides for sphinx_fonts, cli_usage_lexer, and related modules

Author: tony

pyproject.toml

@@ -120,15 +120,6 @@ files = [
   "tests/",
 ]
 
-[[tool.mypy.overrides]]
-module = [
-  "sphinx_fonts",
-  "cli_usage_lexer",
-  "argparse_lexer",
-  "argparse_roles",
-]
-ignore_missing_imports = true
-
 [tool.ruff]
 target-version = "py310"