add doc to `is_inside`

src/fec.rs

@@ -217,6 +217,10 @@ mod tests {
         F::from_le_bytes_mod_order(&n.to_le_bytes())
     }
 
+    /// `is_inside(set, x)` is true iif `x` fully contains one of the lists from `set`
+    ///
+    /// > **Note**  
+    /// > see [`exclusion`] for some example
     fn is_inside(set: &[Vec<usize>], x: &[usize]) -> bool {
         set.iter().any(|y| y.iter().all(|z| x.contains(z)))
     }