BREAKING CHANGE: The `render` method on `Renderer`, `HelpRequest`, and
`ProgramCollect` now returns `RenderResult` instead of taking
`&mut RenderResult`. The `r_print!` and `r_println!` macros have been
removed in favor of using `std::io::Write` directly on `RenderResult`.

Add the `pathf` feature to mingling dependency and invoke
`analyze_and_build_type_mapping` during the build script.

Reorganize internal module visibility from `mod + pub use` to
direct `pub mod`.

Parse fenced code blocks as key-value pairs and checkbox lines as
namespace toggles in a single pass

Extract duplicate `MockCollect` implementations into a reusable
`MockProgramCollect` type. Conditionally require `Serialize` on the
`Groupped` trait when the `general_renderer` feature is enabled.