fix: ProveNamespace godoc (#167)

Closes #123

nmt.go

@@ -185,8 +185,7 @@ func (n *NamespacedMerkleTree) ProveRange(start, end int) (Proof, error) {
 // ProveNamespace returns a range proof for the given NamespaceID.
 //
 // case 1) If the namespace nID is out of the range of the tree's min and max
-// namespace i.e., (nID < n.minNID) or (n.maxNID < nID) ProveNamespace returns
-// an error and does not generate any range proof, instead it returns an empty
+// namespace i.e., (nID < n.minNID) or (n.maxNID < nID) ProveNamespace returns an empty
 // Proof with empty nodes and the range (0,0) i.e., Proof.start = 0 and
 // Proof.end = 0 to indicate that this namespace is not contained in the tree.
 //
@@ -216,7 +215,7 @@ func (n *NamespacedMerkleTree) ProveRange(start, end int) (Proof, error) {
 func (n *NamespacedMerkleTree) ProveNamespace(nID namespace.ID) (Proof, error) {
 	isMaxNsIgnored := n.treeHasher.IsMaxNamespaceIDIgnored()
 	// case 1) In the cases (n.nID < minNID) or (n.maxNID < nID), return empty
-	// range and no proof
+	// range proof
 	if nID.Less(n.minNID) || n.maxNID.Less(nID) {
 		return NewEmptyRangeProof(isMaxNsIgnored), nil
 	}