[Gradle] Simplify optInAnnotation function name to optIn in DSL

#KT-38111

libraries/tools/kotlin-gradle-plugin-api/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/LanguageSettingsBuilder.kt

@@ -18,10 +18,10 @@ interface LanguageSettingsBuilder : LanguageSettings {
 
     override val enabledLanguageFeatures: Set<String>
 
-    @Deprecated("Unsupported and will be removed in next major releases", replaceWith = ReplaceWith("optInAnnotation(name)"))
+    @Deprecated("Unsupported and will be removed in next major releases", replaceWith = ReplaceWith("optIn(name)"))
     fun useExperimentalAnnotation(name: String)
 
-    fun optInAnnotation(name: String)
+    fun optIn(annotationName: String)
 
     override val experimentalAnnotationsInUse: Set<String>
 }

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/kotlin/org/jetbrains/kotlin/gradle/NewMultiplatformIT.kt

@@ -730,8 +730,8 @@ class NewMultiplatformIT : BaseGradleIT() {
                         // languageVersion = '1.4'
                         // apiVersion = '1.4'
                         enableLanguageFeature('InlineClasses')
-                        optInAnnotation('kotlin.ExperimentalUnsignedTypes')
+                        optIn('kotlin.ExperimentalUnsignedTypes')
-                        optInAnnotation('kotlin.contracts.ExperimentalContracts')
+                        optIn('kotlin.contracts.ExperimentalContracts')
                         progressiveMode = true
                     }
                     project.ext.set("kotlin.mpp.freeCompilerArgsForSourceSet.${'$'}name", ["-Xno-inline"])
@@ -824,7 +824,7 @@ class NewMultiplatformIT : BaseGradleIT() {
         )
 
         testMonotonousCheck(
-            "languageSettings.optInAnnotation('kotlin.ExperimentalUnsignedTypes')",
+            "languageSettings.optIn('kotlin.ExperimentalUnsignedTypes')",
             "The dependent source set must use all opt-in annotations that its dependency uses."
         )
 

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/commonizeCurlInterop/build.gradle.kts

@@ -21,7 +21,7 @@ kotlin {
     targetBMain.dependsOn(nativeMain)
 
     sourceSets.all {
-        languageSettings.optInAnnotation("kotlin.RequiresOptIn")
+        languageSettings.optIn("kotlin.RequiresOptIn")
     }
 
     targetA.compilations.getByName("main").cinterops.create("curl")

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/commonizeHierarchically/p1/build.gradle.kts

@@ -75,7 +75,7 @@ kotlin {
 
 
     sourceSets.all {
-        languageSettings.optInAnnotation("kotlin.RequiresOptIn")
+        languageSettings.optIn("kotlin.RequiresOptIn")
     }
 
     targets.withType<KotlinNativeTarget>().forEach { target ->

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/commonizeHierarchicallyMultiModule/p1/build.gradle.kts

@@ -68,7 +68,7 @@ kotlin {
 
 
     sourceSets.all {
-        languageSettings.optInAnnotation("kotlin.RequiresOptIn")
+        languageSettings.optIn("kotlin.RequiresOptIn")
     }
 
     targets.withType<KotlinNativeTarget>().forEach { target ->

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/commonizeHierarchicallyMultiModule/p2/build.gradle.kts

@@ -71,7 +71,7 @@ kotlin {
     }
 
     sourceSets.all {
-        languageSettings.optInAnnotation("kotlin.RequiresOptIn")
+        languageSettings.optIn("kotlin.RequiresOptIn")
     }
 
     targets.withType<KotlinNativeTarget>().forEach { target ->

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/commonizeHierarchicallyMultiModule/p3/build.gradle.kts

@@ -67,7 +67,7 @@ kotlin {
     }
 
     sourceSets.all {
-        languageSettings.optInAnnotation("kotlin.RequiresOptIn")
+        languageSettings.optIn("kotlin.RequiresOptIn")
     }
 
     targets.withType<KotlinNativeTarget>().forEach { target ->

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/commonizeInteropUsingPosixApis/build.gradle.kts

@@ -22,7 +22,7 @@ kotlin {
     targetBMain.dependsOn(nativeMain)
 
     sourceSets.all {
-        languageSettings.optInAnnotation("kotlin.RequiresOptIn")
+        languageSettings.optIn("kotlin.RequiresOptIn")
     }
 
     targetA.compilations.getByName("main").cinterops.create("withPosix") {

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/commonizeSQLiteAndCurlInterop/build.gradle.kts

@@ -21,7 +21,7 @@ kotlin {
     targetBMain.dependsOn(nativeMain)
 
     sourceSets.all {
-        languageSettings.optInAnnotation("kotlin.RequiresOptIn")
+        languageSettings.optIn("kotlin.RequiresOptIn")
     }
 
     targetA.compilations.getByName("main").cinterops.create("sqlite")

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/commonizeSQLiteInterop/build.gradle.kts

@@ -21,7 +21,7 @@ kotlin {
     targetBMain.dependsOn(nativeMain)
 
     sourceSets.all {
-        languageSettings.optInAnnotation("kotlin.RequiresOptIn")
+        languageSettings.optIn("kotlin.RequiresOptIn")
     }
 
     targetA.compilations.getByName("main").cinterops.create("sqlite")

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/sources/DefaultLanguageSettingsBuilder.kt

@@ -77,8 +77,8 @@ internal class DefaultLanguageSettingsBuilder(@Transient private val project: Pr
             return optInAnnotationsInUse
         }
 
-    override fun optInAnnotation(name: String) {
+    override fun optIn(annotationName: String) {
-        optInAnnotationsInUseImpl += name
+        optInAnnotationsInUseImpl += annotationName
     }
 
     override fun useExperimentalAnnotation(name: String) {
@@ -86,9 +86,9 @@ internal class DefaultLanguageSettingsBuilder(@Transient private val project: Pr
             project,
             "Kotlin language settings function",
             "useExperimentalAnnotation",
-            "optInAnnotation"
+            "optIn"
         )
-        optInAnnotation(name)
+        optIn(name)
     }
 
     /* A Kotlin task that is responsible for code analysis of the owner of this language settings builder. */