Function extract_docs 

pub(crate) fn extract_docs<'a, 'db>(
    db: &'db dyn SourceDatabase,
    krate: Crate,
    resolver: &dyn Fn() -> Resolver<'db>,
    get_cfg_options: &dyn Fn() -> &'a CfgOptions,
    source: InFile<AnyHasAttrs>,
    outer_mod_decl: Option<InFile<Module>>,
    inner_attrs_node: Option<SyntaxNode>,
) -> Option<Box<Docs>>