Add no-std::no-alloc category

Author: dtolnay

serde/Cargo.toml

@@ -3,7 +3,7 @@ name = "serde"
 version = "1.0.165" # remember to update html_root_url and serde_derive dependency
 authors = ["Erick Tryzelaar <[email protected]>", "David Tolnay <[email protected]>"]
 build = "build.rs"
-categories = ["encoding", "no-std"]
+categories = ["encoding", "no-std", "no-std::no-alloc"]
 description = "A generic serialization/deserialization framework"
 documentation = "https://docs.rs/serde"
 homepage = "https://serde.rs"