refactor: Turn off unused features in dependencies

Author: Kogia-sima

sailfish-compiler/Cargo.toml

@@ -30,7 +30,7 @@ home = "0.5.3"
 [dependencies.syn]
 version = "1.0.21"
 default-features = false
-features = ["parsing", "full", "visit-mut", "printing", "clone-impls", "extra-traits"]
+features = ["parsing", "full", "visit-mut", "printing"]
 
 [dependencies.proc-macro2]
 version = ">=1.0.11, <=1.0.24"