Function replace_text 

pub fn replace_text(
    doc: &mut Document,
    page_num: u32,
    search: &str,
    replacement: &str,
    _fonts: &FontMap,
) -> Result<usize>

Replace all occurrences of search with replacement in a page’s content.

Returns the number of occurrences replaced. Occurrences that cannot be replaced (unencodable characters, unsupported containers such as Form XObjects, /ActualText-covered spans) do not count and are not errors. The replacement is encoded in the original font when possible; otherwise a Helvetica/WinAnsiEncoding fallback font is injected and reported through the crate::text_edit API (this wrapper only returns the count).

The fonts parameter is retained for signature compatibility; the engine builds its own font map.