Fix incompatibility with mods which mixin into Main (fixes #327)

src/main/java/com/replaymod/core/DummyChainLoadEntryPoint.java

@@ -0,0 +1,18 @@
+//#if FABRIC>=1
+package com.replaymod.core;
+
+import net.fabricmc.loader.api.entrypoint.PreLaunchEntrypoint;
+
+// Required for ReplayModMMLauncher.
+//
+// Chain-loading mixin configurations only works when the first class that is loaded doesn't have any mixins which
+// target it. The first class would ordinarily be MC's Main but there are valid use cases for targeting it, see
+// e.g. https://github.com/ReplayMod/ReplayMod/issues/327
+// So, instead of relying on the bad assumption that Main doesn't have any mixins, we'll instead register this
+// dummy pre-launch entry point which is practically guaranteed to not have any mixins and gets called before Main.
+public class DummyChainLoadEntryPoint implements PreLaunchEntrypoint {
+    @Override
+    public void onPreLaunch() {
+    }
+}
+//#endif

src/main/resources/fabric.mod.json

@@ -25,6 +25,9 @@
     "modmenu": [
       "com.replaymod.core.gui.ModMenuApiImpl"
     ],
+    "preLaunch": [
+      "com.replaymod.core.DummyChainLoadEntryPoint"
+    ],
     "mm:early_risers": [
       "com.replaymod.core.ReplayModMMLauncher"
     ]