Rename "data" and "network" codecs to "server" and "client" codecs (#4424)

The sided names avoid confusing modders into thinking that the client codec
is only used for syncing since it also reads data pack contents.

(cherry picked from commit 742bac29fb)

fabric-registry-sync-v0/src/main/java/net/fabricmc/fabric/api/event/registry/DynamicRegistries.java

@@ -131,17 +131,22 @@ public final class DynamicRegistries {
 	 * <p>The entries of the registry will be loaded from data packs at the file path
 	 * {@code data/<entry namespace>/<registry namespace>/<registry path>/<entry path>.json}
 	 *
-	 * <p>The registry will be synced from the server to players' clients using the given network codec.
+	 * <p>The registry will be synced from the server to players' clients using the given client codec.
+	 * The client codec is also used for writing synced entries on the server, so it cannot depend on
+	 * client-only code.
+	 *
+	 * <p>The client codec must be able to read data encoded by the server codec.
+	 * This is because client-sided registry entries are sometimes read directly from a data pack using the client codec.
 	 *
 	 * @param key          the unique key of the registry
-	 * @param dataCodec    the codec used to load registry entries from data packs
-	 * @param networkCodec the codec used to load registry entries from the network
+	 * @param serverCodec  the codec used to load registry entries on the server
+	 * @param clientCodec  the codec used to load registry entries on the client and sync them from the server
 	 * @param options      options to configure syncing
 	 * @param <T>          the entry type of the registry
 	 */
-	public static <T> void registerSynced(RegistryKey<? extends Registry<T>> key, Codec<T> dataCodec, Codec<T> networkCodec, SyncOption... options) {
-		DynamicRegistriesImpl.register(key, dataCodec);
-		DynamicRegistriesImpl.addSyncedRegistry(key, networkCodec, options);
+	public static <T> void registerSynced(RegistryKey<? extends Registry<T>> key, Codec<T> serverCodec, Codec<T> clientCodec, SyncOption... options) {
+		DynamicRegistriesImpl.register(key, serverCodec);
+		DynamicRegistriesImpl.addSyncedRegistry(key, clientCodec, options);
 	}
 
 	/**

fabric-registry-sync-v0/src/main/java/net/fabricmc/fabric/impl/registry/sync/DynamicRegistriesImpl.java

@@ -51,30 +51,30 @@ public final class DynamicRegistriesImpl {
 		return List.copyOf(DYNAMIC_REGISTRIES);
 	}
 
-	public static <T> RegistryLoader.Entry<T> register(RegistryKey<? extends Registry<T>> key, Codec<T> codec) {
+	public static <T> RegistryLoader.Entry<T> register(RegistryKey<? extends Registry<T>> key, Codec<T> serverCodec) {
 		Objects.requireNonNull(key, "Registry key cannot be null");
-		Objects.requireNonNull(codec, "Codec cannot be null");
+		Objects.requireNonNull(serverCodec, "Server codec cannot be null");
 
 		if (!DYNAMIC_REGISTRY_KEYS.add(key)) {
 			throw new IllegalArgumentException("Dynamic registry " + key + " has already been registered!");
 		}
 
-		var entry = new RegistryLoader.Entry<>(key, codec, false);
+		var entry = new RegistryLoader.Entry<>(key, serverCodec, false);
 		DYNAMIC_REGISTRIES.add(entry);
 		FABRIC_DYNAMIC_REGISTRY_KEYS.add(key);
 		return entry;
 	}
 
-	public static <T> void addSyncedRegistry(RegistryKey<? extends Registry<T>> key, Codec<T> networkCodec, DynamicRegistries.SyncOption... options) {
+	public static <T> void addSyncedRegistry(RegistryKey<? extends Registry<T>> key, Codec<T> clientCodec, DynamicRegistries.SyncOption... options) {
 		Objects.requireNonNull(key, "Registry key cannot be null");
-		Objects.requireNonNull(networkCodec, "Network codec cannot be null");
+		Objects.requireNonNull(clientCodec, "Client codec cannot be null");
 		Objects.requireNonNull(options, "Options cannot be null");
 
 		if (!(RegistryLoader.SYNCED_REGISTRIES instanceof ArrayList<RegistryLoader.Entry<?>>)) {
 			RegistryLoader.SYNCED_REGISTRIES = new ArrayList<>(RegistryLoader.SYNCED_REGISTRIES);
 		}
 
-		RegistryLoader.SYNCED_REGISTRIES.add(new RegistryLoader.Entry<>(key, networkCodec, false));
+		RegistryLoader.SYNCED_REGISTRIES.add(new RegistryLoader.Entry<>(key, clientCodec, false));
 
 		if (!(SerializableRegistries.SYNCED_REGISTRIES instanceof HashSet<RegistryKey<? extends Registry<?>>>)) {
 			SerializableRegistries.SYNCED_REGISTRIES = new HashSet<>(SerializableRegistries.SYNCED_REGISTRIES);