Function source_meanings_in 

pub fn source_meanings_in(
    records: &[ConceptRecord],
    register: &FoundationRegister,
    alias: &SourceAlias,
    within: Option<&str>,
) -> Vec<String>

Returns the concepts and foundation models a source spelling means, optionally only those under within.

A concept record matches an alias with the same source and name; a foundation model matches when its alias for the source lists the name among its comma-separated spellings.