K2 kapt: remove reference to "kapt 4" from the warning

#KT-62438 Fixed

compiler/cli/src/org/jetbrains/kotlin/cli/common/arguments.kt

@@ -79,7 +79,7 @@ private fun switchToFallbackModeIfNecessary(arguments: CommonCompilerArguments,
             arguments.allowUnstableDependencies = true
         }
         arguments.useKapt4 -> warn(
-            if (isK2) "Kapt 4 is an experimental feature. Use with caution."
+            if (isK2) "K2 kapt is an experimental feature. Use with caution."
             else "-Xuse-kapt4 flag can be only used with language version 2.0+."
         )
     }

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/kotlin/org/jetbrains/kotlin/gradle/Kapt3IT.kt

@@ -1313,12 +1313,12 @@ open class Kapt3IT : Kapt3BaseIT() {
                 assertKaptSuccessful()
                 assertTasksExecuted(":kaptGenerateStubsKotlin", ":kaptKotlin", ":compileKotlin")
                 assertOutputDoesNotContain("Falling back to 1.9.")
-                assertOutputContains("Kapt 4 is an experimental feature. Use with caution.")
+                assertOutputContains("K2 kapt is an experimental feature. Use with caution.")
             }
             build("-Pkapt.use.k2=true", "cleanCompileKotlin", "compileKotlin") {
                 assertTasksExecuted(":compileKotlin")
                 // The warning should not be displayed for the compile task.
-                assertOutputDoesNotContain("Kapt 4 is an experimental feature. Use with caution.")
+                assertOutputDoesNotContain("K2 kapt is an experimental feature. Use with caution.")
             }
         }
     }