New: Support Enum extensions.

Author: LlamaLad7

src/main/kotlin/platform/mixin/inspection/MixinClassTypeInspection.kt

@@ -22,6 +22,7 @@ package com.demonwav.mcdev.platform.mixin.inspection
 
 import com.demonwav.mcdev.platform.mixin.util.hasAccess
 import com.demonwav.mcdev.platform.mixin.util.isAccessorMixin
+import com.demonwav.mcdev.platform.mixin.util.isFabricMixin
 import com.demonwav.mcdev.platform.mixin.util.isMixin
 import com.demonwav.mcdev.platform.mixin.util.mixinTargets
 import com.intellij.codeInspection.LocalQuickFix
@@ -68,7 +69,7 @@ class MixinClassTypeInspection : MixinInspection() {
                 }
             }
 
-            if (mixinClass.isEnum) {
+            if (mixinClass.isEnum && !mixinClass.isFabricMixin) {
                 holder.registerProblem(problemElement, "Mixins cannot be enums", *fixes.toTypedArray())
                 return
             }

src/main/kotlin/platform/mixin/inspection/StaticMemberInspection.kt

@@ -30,6 +30,7 @@ import com.intellij.codeInsight.intention.QuickFixFactory
 import com.intellij.codeInspection.ProblemsHolder
 import com.intellij.psi.JavaElementVisitor
 import com.intellij.psi.PsiElementVisitor
+import com.intellij.psi.PsiEnumConstant
 import com.intellij.psi.PsiField
 import com.intellij.psi.PsiMember
 import com.intellij.psi.PsiMethod
@@ -71,7 +72,7 @@ class StaticMemberInspection : MixinInspection() {
 
         private fun isProblematic(member: PsiMember): Boolean {
             val containingClass = member.containingClass ?: return false
-            if (!containingClass.isMixin) {
+            if (!containingClass.isMixin || member is PsiEnumConstant) {
                 return false
             }
 

src/main/kotlin/platform/mixin/inspection/addedMembers/MissingUniqueAnnotationInspection.kt

@@ -24,13 +24,17 @@ import com.demonwav.mcdev.platform.mixin.util.MixinConstants
 import com.intellij.codeInsight.intention.AddAnnotationModCommandAction
 import com.intellij.codeInspection.LocalQuickFix
 import com.intellij.codeInspection.ProblemsHolder
+import com.intellij.psi.PsiEnumConstant
 import com.intellij.psi.PsiField
 import com.intellij.psi.PsiMethod
 
 class MissingUniqueAnnotationInspection : AbstractAddedMembersInspection() {
     override fun getStaticDescription() = "Reports missing @Unique annotations"
 
     override fun visitAddedField(holder: ProblemsHolder, field: PsiField) {
+        if (field is PsiEnumConstant) {
+            return
+        }
         if (!field.hasAnnotation(MixinConstants.Annotations.UNIQUE)) {
             holder.registerProblem(
                 field.nameIdentifier,