strengthen the wording in docs

Co-authored-by: Philipp Gackstatter <PhilippGackstatter@users.noreply.github.com>

miden-crypto/src/merkle/path.rs

@@ -29,7 +29,7 @@ impl MerklePath {
 
     /// Creates a new Merkle path from a list of nodes.
     ///
-    /// The list is assumed to be in order of deepest to shallowest.
+    /// The list must be in order of deepest to shallowest.
     pub fn new(nodes: Vec<RpoDigest>) -> Self {
         assert!(nodes.len() <= u8::MAX.into(), "MerklePath may have at most 256 items");
         Self { nodes }