Fix mypy 2.4 errors and enable warn_unused_ignores

[tleonhardt]

Summary

mypy 2.4.0 switched to its new Ruff-based native parser by default. That parser rejects third-party codes such as ty:unresolved-attribute inside # type: ignore[...] comments, so every combined mypy/ty ignore in cmd2/ produced an Invalid "type: ignore" comment [syntax] error and stopped suppressing the diagnostic it was there for (75 errors in total). Running with --no-native-parser produced no errors, so nothing else in 2.4 affects cmd2.

Commit 1: Split combined ignore comments

The 43 combined comments are now two separate pragmas:

# before
action.get_nargs_range()  # type: ignore[attr-defined, ty:unresolved-attribute]
# after
action.get_nargs_range()  # type: ignore[attr-defined]  # ty: ignore[unresolved-attribute]

This form works with mypy's native and legacy parsers and with ty. The mypy pragma has to come first, and ty still needs its own rule code. This also bumps the ruff pre-commit hook to v0.16.10.

Commit 2: Enable warn_unused_ignores and remove stale ignores

warn_unused_ignores was turned off because mypy's legacy parser reported every ty: code as unused. With the comments split it can be turned back on. That exposed 25 stale or platform-specific ignores. I checked each one with Python 3.11–3.15 on linux, darwin, and win32 so that ignores needed only on some platforms or versions are kept:

• Removed: 18 ignores that are unused in every configuration. Where a line also had a ty code, the # ty: ignore[...] half stays.
• Narrowed: the AnsiDecoder.decode monkey-patch ignore, from assignment to method-assign.
• NoConsoleScreenBufferError: now [no-redef, unused-ignore], because the redefinition only exists on win32.
• Cmd2HelpFormatter._set_color(): uses if sys.version_info >= (3, 14): instead of an early return. mypy skips version-guarded blocks instead of reporting the rest of the method as unreachable on older Pythons. Behavior is unchanged.
• Cmd._initial_termios_settings: annotated as list[Any] | None, with an explicit not sys.platform.startswith("win") check added to the two termios restore conditions. mypy had inferred the attribute as always None on win32, so it never checked that POSIX-only code there. The new check changes nothing at runtime: the attribute is always None on Windows, and the termios tests already skip on Windows.

Testing

• make check, make test, and make docs-test pass.
• mypy 2.4.0 passes with warn_unused_ignores = true for Python 3.11, 3.12, 3.13, 3.14, and 3.15, each on linux, darwin, and win32. The 3.11–3.14 runs used environments built like the TypeCheck workflow's (--no-default-groups --group validate).
• ty passes in the 3.11 and 3.14 environments, and reports no unused ty: ignore comments with --warn unused-ignore-comment.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.66%. Comparing base (89bf0a0) to head (1553bf8).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1768      +/-   ##
==========================================
- Coverage   99.66%   99.66%   -0.01%     
==========================================
  Files          23       23              
  Lines        5974     5973       -1     
==========================================
- Hits         5954     5953       -1     
  Misses         20       20              

Flag	Coverage Δ
unittests	99.66% <100.00%> (-0.01%)	⬇️

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