Reorganize dependencies in Cargo.toml

Cargo.toml

@@ -37,14 +37,16 @@ all-languages = [
 ]
 
 [dependencies]
-bitcoin_hashes = { version = "0.11.0", default-features = false }
 rand_core = ">=0.4.0, <0.7.0"
-
-unicode-normalization = { version = "=0.1.9", optional = true }
 rand = { version = ">=0.6.0, <0.9.0", optional = true }
 serde = { version = "1.0", default-features = false, features = [ "alloc" ], optional = true }
+
 # Enabling this feature raises the MSRV to 1.51
-zeroize = {version = "1.5", features = ["zeroize_derive"], optional = true}
+zeroize = { version = "1.5", features = ["zeroize_derive"], optional = true }
+
+# Unexported dependnecies
+bitcoin_hashes = { version = "0.11.0", default-features = false }
+unicode-normalization = { version = "=0.1.9", optional = true }
 
 [dev-dependencies]
 rand = { version = "0.8.5", optional = false }