Use ? instead of unwrap() in examples

nalgebra-sparse/src/io/matrix_market.rs

@@ -1439,6 +1439,7 @@ fn next_dense_coordinate(
 /// --------
 /// ```
 /// # use nalgebra_sparse::CooMatrix;
+/// # fn main() -> Result<(), Box<dyn std::error::Error>> {
 /// use nalgebra_sparse::io::{save_to_matrix_market_str};
 /// let expected_str = r#"%%matrixmarket matrix coordinate integer general
 /// % matrixmarket file generated by nalgebra-sparse.
@@ -1449,9 +1450,10 @@ fn next_dense_coordinate(
 /// let row_indices = vec![0,1];
 /// let col_indices = vec![0,2];
 /// let values = vec![10,5];
-/// let matrix = CooMatrix::try_from_triplets(5,4,row_indices,col_indices,values).unwrap();
+/// let matrix = CooMatrix::try_from_triplets(5,4,row_indices,col_indices,values)?;
 /// let generated_matrixmarket_str = save_to_matrix_market_str(&matrix);
 /// assert_eq!(expected_str,generated_matrixmarket_str);
+/// # Ok(()) }
 /// ```
 pub fn save_to_matrix_market_str<T, S>(
     sparse_matrix: &S,
@@ -1482,6 +1484,7 @@ where
 /// Examples
 /// --------
 /// ```no_run
+/// # fn main() -> Result<(), Box<dyn std::error::Error>> {
 /// use nalgebra_sparse::io::{save_to_matrix_market_file,load_coo_from_matrix_market_str};
 /// let str = r#"
 /// %%matrixmarket matrix coordinate integer general
@@ -1489,8 +1492,9 @@ where
 /// 1 1 10
 /// 2 3 5
 /// "#;
-/// let matrix = load_coo_from_matrix_market_str::<i32>(&str).unwrap();
-/// save_to_matrix_market_file(&matrix,"path/to/matrix.mtx").unwrap();
+/// let matrix = load_coo_from_matrix_market_str::<i32>(&str)?;
+/// save_to_matrix_market_file(&matrix,"path/to/matrix.mtx")?;
+/// # Ok(()) }
 /// ```
 pub fn save_to_matrix_market_file<T, S, P>(
     sparse_matrix: &S,