Function replace_toc_in_text 

pub fn replace_toc_in_text(
    current_text: &str,
    new_toc: &str,
) -> TocReplaceResult

Attempt to find and replace an existing <!-- TOC -->...<!-- /TOC --> block in current_text with new_toc.

Returns:

• TocReplaceResult::NoMarkers when no markers were found
• TocReplaceResult::NoChange when the existing block equals new_toc
• TocReplaceResult::Updated with the new full source text otherwise