Why Am I Getting A GenericSignatureFormatError?

Exception:

[22:28:44 ERROR]: Error occurred while enabling ColoredEverything v1.0.0 (Is it up to date?)
java.lang.reflect.GenericSignatureFormatError: Signature Parse error: expected '<' or ';' but got
        Remaining input:  everything/shaded/kotlin/Metadata;
        at sun.reflect.generics.parser.SignatureParser.error(SignatureParser.java:124) ~[?:?]
        at sun.reflect.generics.parser.SignatureParser.parsePackageNameAndSimpleClassTypeSignature(SignatureParser.java:337) ~[?:?]
        at sun.reflect.generics.parser.SignatureParser.parseClassTypeSignature(SignatureParser.java:304) ~[?:?]
        at sun.reflect.generics.parser.SignatureParser.parseFieldTypeSignature(SignatureParser.java:283) ~[?:?]
        at sun.reflect.generics.parser.SignatureParser.parseFieldTypeSignature(SignatureParser.java:277) ~[?:?]
        at sun.reflect.generics.parser.SignatureParser.parseTypeSignature(SignatureParser.java:469) ~[?:?]
        at sun.reflect.generics.parser.SignatureParser.parseTypeSig(SignatureParser.java:188) ~[?:?]
        at sun.reflect.annotation.AnnotationParser.parseSig(AnnotationParser.java:437) ~[?:?]
        at sun.reflect.annotation.AnnotationParser.parseAnnotation2(AnnotationParser.java:242) ~[?:?]
        at sun.reflect.annotation.AnnotationParser.parseAnnotations2(AnnotationParser.java:121) ~[?:?]
        at sun.reflect.annotation.AnnotationParser.parseAnnotations(AnnotationParser.java:73) ~[?:?]
        at java.lang.Class.createAnnotationData(Class.java:3886) ~[?:?]
        at java.lang.Class.annotationData(Class.java:3875) ~[?:?]
        at java.lang.Class.getAnnotation(Class.java:3780) ~[?:?]
        at org.bukkit.plugin.java.JavaPluginLoader.createRegisteredListeners(JavaPluginLoader.java:326) ~[patched_1.16.1.jar:git-Paper-130]
        at org.bukkit.plugin.SimplePluginManager.registerEvents(SimplePluginManager.java:639) ~[patched_1.16.1.jar:git-Paper-130]
        at com.smushytaco.plugin.Plugin.onEnable(Plugin.kt:11) ~[?:?]
        at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:263) ~[patched_1.16.1.jar:git-Paper-130]
        at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:380) ~[patched_1.16.1.jar:git-Paper-130]
        at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:483) ~[patched_1.16.1.jar:git-Paper-130]
        at org.bukkit.craftbukkit.v1_16_R1.CraftServer.enablePlugin(CraftServer.java:500) ~[patched_1.16.1.jar:git-Paper-130]
        at org.bukkit.craftbukkit.v1_16_R1.CraftServer.enablePlugins(CraftServer.java:414) ~[patched_1.16.1.jar:git-Paper-130]
        at net.minecraft.server.v1_16_R1.MinecraftServer.loadWorld(MinecraftServer.java:471) ~[patched_1.16.1.jar:git-Paper-130]
        at net.minecraft.server.v1_16_R1.DedicatedServer.init(DedicatedServer.java:241) ~[patched_1.16.1.jar:git-Paper-130]
        at net.minecraft.server.v1_16_R1.MinecraftServer.v(MinecraftServer.java:941) ~[patched_1.16.1.jar:git-Paper-130]
        at net.minecraft.server.v1_16_R1.MinecraftServer.lambda$a$0(MinecraftServer.java:177) ~[patched_1.16.1.jar:git-Paper-130]
        at java.lang.Thread.run(Thread.java:832) [?:?]

Main Plugin Class:

package com.smushytaco.plugin
import com.smushytaco.plugin.listeners.*
import org.bukkit.Bukkit
import org.bukkit.plugin.java.JavaPlugin
class Plugin : JavaPlugin() {
    override fun onEnable() {
        Bukkit.getPluginManager().registerEvents(ValidationTest, this)
    }
}

ValidationTest Object:

package com.smushytaco.plugin.listeners
import com.smushytaco.plugin.event.ColoredStringUsageIsAllowed
import org.bukkit.event.EventHandler
import org.bukkit.event.Listener
object ValidationTest : Listener {
    @EventHandler
    private fun coloredStringValidation(coloredStringUsageIsAllowed: ColoredStringUsageIsAllowed) {
        if (coloredStringUsageIsAllowed.usage == "Player Public Chat") coloredStringUsageIsAllowed.isCancelled = true
    }
}

ColoredStringUsageIsAllowed Class:

package com.smushytaco.plugin.event
import org.bukkit.event.Cancellable
import org.bukkit.event.Event
import org.bukkit.event.HandlerList
/**
 * Used to determine weather the use of a colored string is permitted. If isCancelled is true then it isn't permitted. If isCancelled is false then it is permitted.
 * @param[usage] Used by listeners of this event to determine weather to cancel the event or not.
 * @param[isAsynchronous] Used to determine weather the event will run asynchronously or not.
 * @author SmushyTaco (https://www.smushytaco.com/)
 */
@Suppress("unused")
class ColoredStringUsageIsAllowed(val usage: String, isAsynchronous: Boolean = false) : Event(isAsynchronous), Cancellable {
    private var isCancelled = false
    companion object {
        private val HANDLERS = HandlerList()
        @JvmStatic private fun getHandlerList(): HandlerList = HANDLERS
    }
    override fun getHandlers(): HandlerList = HANDLERS
    override fun setCancelled(cancel: Boolean) {
        isCancelled = cancel
    }
    override fun isCancelled(): Boolean = isCancelled
}

build.gradle.kts File:

import com.github.jengelman.gradle.plugins.shadow.tasks.ConfigureShadowRelocation
import com.github.jengelman.gradle.plugins.shadow.tasks.ShadowJar
plugins {
    java
    val kotlinVersion: String by System.getProperties()
    kotlin("jvm").version(kotlinVersion)
    id("com.github.johnrengelman.shadow").version("6.0.0")
}
group = "com.smushytaco"
version = "[1.0.0]"
repositories {
    mavenCentral()
    maven("https://papermc.io/repo/repository/maven-public/")
}
dependencies {
    val kotlinVersion: String by System.getProperties()
    implementation(kotlin("stdlib", kotlinVersion))
    //https://papermc.io/javadocs/paper/1.16/overview-summary.html
    compileOnly("com.destroystokyo.paper", "paper-api", "1.16.1-R0.1-SNAPSHOT")
}
val autoRelocate by tasks.register<ConfigureShadowRelocation>("configureShadowRelocation", ConfigureShadowRelocation::class) {
    target = tasks.getByName("shadowJar") as ShadowJar?
    val packageName = "${project.group}.${project.name.toLowerCase()}"
    prefix = "$packageName.shaded"
}
tasks {
    shadowJar {
        archiveClassifier.set("")
        project.configurations.implementation.get().isCanBeResolved = true
        configurations = listOf(project.configurations.implementation.get())
        dependsOn(autoRelocate)
    }
    build {
        dependsOn(shadowJar)
    }
}

What exactly have I done wrong?