Define feature for option_compression advertisement

This adds the new feature bit from
lightning/bolts#825

lightning/src/ln/features.rs

@@ -111,7 +111,7 @@ mod sealed {
 			// Byte 2
 			BasicMPP,
 			// Byte 3
-			ShutdownAnySegwit,
+			CompressionAdvertisement | ShutdownAnySegwit,
 		],
 	});
 	define_context!(NodeContext {
@@ -133,7 +133,7 @@ mod sealed {
 			// Byte 2
 			BasicMPP,
 			// Byte 3
-			ShutdownAnySegwit,
+			CompressionAdvertisement | ShutdownAnySegwit,
 		],
 	});
 	define_context!(ChannelContext {
@@ -316,6 +316,10 @@ mod sealed {
 	define_feature!(17, BasicMPP, [InitContext, NodeContext, InvoiceContext],
 		"Feature flags for `basic_mpp`.", set_basic_mpp_optional, set_basic_mpp_required,
 		supports_basic_mpp, requires_basic_mpp);
+	define_feature!(25, CompressionAdvertisement, [InitContext, NodeContext],
+		"Feature flags for `option_compression`.", set_compression_advertisement_optional,
+		set_compression_advertisement_required, supports_compression_advertisement,
+		requires_compression_advertisement);
 	define_feature!(27, ShutdownAnySegwit, [InitContext, NodeContext],
 		"Feature flags for `opt_shutdown_anysegwit`.", set_shutdown_any_segwit_optional,
 		set_shutdown_any_segwit_required, supports_shutdown_anysegwit, requires_shutdown_anysegwit);
@@ -670,6 +674,11 @@ mod tests {
 		assert!(InitFeatures::known().supports_shutdown_anysegwit());
 		assert!(NodeFeatures::known().supports_shutdown_anysegwit());
 
+		assert!(InitFeatures::known().supports_compression_advertisement());
+		assert!(NodeFeatures::known().supports_compression_advertisement());
+		assert!(!InitFeatures::known().requires_compression_advertisement());
+		assert!(!NodeFeatures::known().requires_compression_advertisement());
+
 		let mut init_features = InitFeatures::known();
 		assert!(init_features.initial_routing_sync());
 		init_features.clear_initial_routing_sync();
@@ -709,7 +718,7 @@ mod tests {
 			assert_eq!(node_features.flags[0], 0b00000010);
 			assert_eq!(node_features.flags[1], 0b01010001);
 			assert_eq!(node_features.flags[2], 0b00000010);
-			assert_eq!(node_features.flags[3], 0b00001000);
+			assert_eq!(node_features.flags[3], 0b00001010);
 		}
 
 		// Check that cleared flags are kept blank when converting back: