docs: fix nonce type from int32 to uint32 in documentation

docs/architecture/adr-001-node-key-refactoring.md

@@ -30,7 +30,7 @@ New node structure
 ```go
 type NodeKey struct {
 	version int64
-	nonce   int32
+	nonce   uint32
 }
 
 type Node struct {

docs/node/node.md

@@ -8,7 +8,7 @@ The Node struct stores a node in the IAVL tree.
 // NodeKey represents a key of node in the DB.
 type NodeKey struct {
 	version int64	// version of the IAVL that this node was first added in
-	nonce   int32	// local nonce for the same version
+	nonce   uint32	// local nonce for the same version
 }
 
 // Node represents a node in a Tree.

node.go

@@ -174,7 +174,7 @@ func MakeNode(nk, buf []byte) (*Node, error) {
 			buf = buf[n:]
 			leftNodeKey.nonce = uint32(nonce) // nolint:gosec // we perform the check in the line below
 			if nonce != int64(leftNodeKey.nonce) {
-				return nil, errors.New("invalid leftNodeKey.nonce, out of int32 range")
+				return nil, errors.New("invalid leftNodeKey.nonce, out of uint32 range")
 			}
 			node.leftNodeKey = leftNodeKey.GetKey()
 		}
@@ -199,7 +199,7 @@ func MakeNode(nk, buf []byte) (*Node, error) {
 			}
 			rightNodeKey.nonce = uint32(nonce) // nolint:gosec // we perform the check in the line below
 			if nonce != int64(rightNodeKey.nonce) {
-				return nil, errors.New("invalid rightNodeKey.nonce, out of int32 range")
+				return nil, errors.New("invalid rightNodeKey.nonce, out of uint32 range")
 			}
 			node.rightNodeKey = rightNodeKey.GetKey()
 		}