Use JEP 92 for supported features

Author: lionel-

crates/amalthea/src/wire/kernel_info_reply.rs

@@ -41,8 +41,8 @@ pub struct KernelInfoReplyFull {
     /// Version of messaging protocol
     pub protocol_version: String,
 
-    /// Unofficial feature flag to indicate that the kernel implements JEP 65.
-    pub support_iopub_welcome: bool,
+    /// List of feature flags supported by the kernel. See JEP 92.
+    pub supported_features: Vec<String>,
 
     /// The execution status ("ok" or "error")
     pub status: Status,
@@ -72,7 +72,7 @@ impl From<KernelInfoReply> for KernelInfoReplyFull {
         Self {
             // These fields are set by Amalthea
             protocol_version: String::from("5.4"),
-            support_iopub_welcome: true,
+            supported_features: vec![String::from("iopub_welcome")],
 
             // These fields are set by the Amalthea user
             status: value.status,

crates/amalthea/tests/client.rs

@@ -38,6 +38,8 @@ fn test_amalthea_kernel_info() {
         frontend.recv_shell(),
         Message::KernelInfoReply(reply) => {
             assert_eq!(reply.content.language_info.name, "Test");
+            assert_eq!(reply.content.protocol_version, "5.4");
+            assert!(reply.content.supported_features.contains(&String::from("iopub_welcome")));
         }
     );