Fix use of Fabric internals. Fixes #6.

Author: fnuecke

fabric/src/main/java/li/cil/manual/client/fabric/MarkdownManualFabric.java

@@ -3,13 +3,15 @@
 import li.cil.manual.api.platform.FabricManualInitializer;
 import li.cil.manual.client.ClientSetup;
 import net.fabricmc.api.ClientModInitializer;
-import net.fabricmc.loader.impl.entrypoint.EntrypointUtils;
+import net.fabricmc.loader.api.FabricLoader;
 
 public final class MarkdownManualFabric implements ClientModInitializer {
     @Override
     public void onInitializeClient() {
         ClientSetup.initialize();
 
-        EntrypointUtils.invoke("markdown_manual:registration", FabricManualInitializer.class, FabricManualInitializer::registerManualObjects);
+        FabricLoader.getInstance()
+            .getEntrypoints("markdown_manual:registration", FabricManualInitializer.class)
+            .forEach(FabricManualInitializer::registerManualObjects);
     }
 }