Refactor for clearer and more performant code

[Shute052]

Simplified PR #463 to refactor for clearer and more performant code.

Changelog

Logic Refactoring

• Refactored DeadZoneShape::cross_deadzone_value() and DeadZoneShape::ellipse_deadzone_value() to improve clarity of logic.
• Refactored InputStreams::button_pressed() and InputStreams::input_value() functions for both MouseWheel and MouseMotion events by using more efficient f64 accumulation, reducing unnecessary match.

Deduplication

• Extracted ActionState::action_data_mut_or_default() function to remove duplication in the parts checking press(), release(), and consume().
• Extracted deadzone_axis_value() to remove duplication in the parts applying deadzone to input values.
• Reused the existing virtual_axis_button_clash() for checking clashes of VirtualAxis.
• Extracted send_keyboard_input(), send_mouse_wheel(), send_mouse_motion(), and send_gamepad_button_changed() for MutableInputStreams when mocking input.
• Extracted collect_events_cloned() to remove duplication in the parts collecting the cloned events of MouseWheel and MouseMotion.
• Reused the existing InputStreams::extract_dual_axis_data() to check InputKind::DualAxis has been button_pressed().
• Extracted get_gamepad_value() closure to reuse the logic getting values from InputStreams::gamepad_axes and InputStreams::gamepad_buttons_axes.
• Extracted InputStreams::extract_single_axis_data() for computing the input_value() of VirtualAxis and the input_axis_pair() of VirtualDpad.
• Extracted RawInputs::merge_input_data() to remove duplication in the parts merging UserInputs into a RawInputs.

Code Quality

• Used the existing std::consts like FRAC_PI_2 rather than magic numbers.
• Used f32::from() rather than manual if when just getting a f32 from bool value.
• Used matches! rather than manual match when just getting a bool field value inside Option.
• Used if let Some() rather than manual match when the None arm does nothing.
• Used Result::ok() rather than manual match when casting Result into Option.
• Used Option::then() rather than manual match when just mapping its value.
• Used bool::then_some() rather than manual if when just mapping it into Option.
• Used iterators rather than manual for loops when the logic can be replaced with simple and descriptive operators.
• Used Itertools::join() rather than manual for loop when just converting values into a string.
• Used Option::into_iter().chain(Iter) rather than manual if for identical behavior, as they result in the same assembly code.
• Used HashMap::entry().or_default() rather than manual HashMap::raw_entry_mut().or_insert_with() to ensure its value existence.
• Used assert_eq! rather than assert! when asserting two values are equal.

Typo

• Fixed typo in the documentation of DeadZoneShape.

Documentation

• Added missing documentation of UserInput::len() for VirtualAxis.

[Shute052]

Ready for review, with updated changelog in the description.

[alice-i-cecile]

Awesome, thank you! That should make the migration PR much clearer.