Builds RustQ-authored shared sparse helper functions for generated Rustler decoders.
These helpers are used when callers provide :decoder_sources, allowing
RustQ to read the downstream Decoder implementation and infer fallible
method propagation from real Rust metadata.
Summary
Functions
@spec fragments( [Path.t()] | Path.t(), keyword() ) :: [RustQ.Rust.Fragment.t()]
@spec macro_call( atom(), keyword() ) :: RustQ.Rust.Fragment.t()