jid: Remove the std feature

Since Rust 1.81, std::error::Error has been moved to core::error::Error,
which we can use without depending on std.

jid/src/lib.rs

@@ -34,7 +34,7 @@
 
 extern crate alloc;
 
-#[cfg(any(feature = "std", test))]
+#[cfg(test)]
 extern crate std;
 
 use alloc::borrow::Cow;