Convert the gradle config to kotlin.

I moved the description out of the Gradle config and into the XML. (It was just in the gradle so we could add the gjf version number, but that seems unnecessary since I changed the versioning so that the plugin version matches the gjf version.)

I also updated the IntelliJ Gradle plugin to 1.13.1 because plugin publishing is broken in 1.13.0.

PiperOrigin-RevId: 513888985

idea_plugin/build.gradle.kts

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2017 Google Inc. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+plugins { id("org.jetbrains.intellij") version "1.13.1" }
+
+apply(plugin = "org.jetbrains.intellij")
+
+apply(plugin = "java")
+
+repositories { mavenCentral() }
+
+val googleJavaFormatVersion = "1.16.0"
+
+java {
+  sourceCompatibility = JavaVersion.VERSION_11
+  targetCompatibility = JavaVersion.VERSION_11
+}
+
+intellij {
+  pluginName.set("google-java-format")
+  plugins.set(listOf("java"))
+  version.set("2021.3")
+}
+
+tasks {
+  patchPluginXml {
+    version.set("${googleJavaFormatVersion}.0")
+    sinceBuild.set("213")
+    untilBuild.set("")
+  }
+
+  publishPlugin {
+    val jetbrainsPluginRepoToken: String by project
+    token.set(jetbrainsPluginRepoToken)
+  }
+
+  withType<Test>().configureEach {
+    jvmArgs(
+      "--add-exports jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED",
+      "--add-exports jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED",
+      "--add-exports jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED",
+      "--add-exports jdk.compiler/com.sun.tools.javac.parser=ALL-UNNAMED",
+      "--add-exports jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED",
+      "--add-exports jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED",
+    )
+  }
+}
+
+dependencies {
+  implementation("com.google.googlejavaformat:google-java-format:${googleJavaFormatVersion}")
+  testImplementation("junit:junit:4.13.2")
+  testImplementation("com.google.truth:truth:1.1.3")
+}

idea_plugin/src/main/resources/META-INF/plugin.xml

@@ -26,6 +26,13 @@
   <depends>com.intellij.modules.lang</depends>
   <depends>com.intellij.modules.platform</depends>
 
+  <description><![CDATA[
+    Formats source code using the google-java-format tool.<p>
+
+    This plugin requires additional IDE configuration. For more information,
+    <a href="https://github.com/google/google-java-format/blob/master/README.md#intellij-jre-config">read
+    the documentation.</a>
+  ]]></description>
   <change-notes><![CDATA[
     <dl>
       <dt>1.16.0.0</dt>