Function validate_internal_links 

pub fn validate_internal_links(
    outbound: &[OutboundLink],
    resolver_config: &PathResolverConfig<'_>,
) -> Vec<PageError>

Validates the internal outbound links for a single page.

Used where there is no rendered body to read hrefs from — tag pages and tag indexes, whose outbound links are synthesized as absolute site URLs rather than authored. For markdown pages use validate_rendered_links, which sees what the renderer actually emitted.