Function parse_text_grid_with_missing 

pub fn parse_text_grid_with_missing(
    content: &str,
    opts: &TextParseOptions,
    missing_values: &[&str],
) -> FerrayResult<(Vec<Option<String>>, usize, usize)>

Parse a delimited text into a 2D grid, allowing missing values.

Missing values (empty cells or cells matching missing_values) are returned as None. Present values are returned as Some(String).