chore(Android): Update Performance V2 docs (#13173)

* update perfv2

* perfv2 snippet line highlights

Author: kahest

docs/platforms/android/tracing/instrumentation/perf-v2.mdx

@@ -4,44 +4,41 @@ sidebar_order: 11
 description: "Learn how to get even more insights into Android app performance"
 ---
 
-<Alert>
+Performance V2 contains a set of features that enrich performance instrumentation. It tightly integrates with the [Mobile Vitals](/product/insights/mobile/mobile-vitals/) Insights module, enabling <PlatformLink to="/tracing/instrumentation/perf-v2/#app-start">App Start</PlatformLink> and <PlatformLink to="/tracing/instrumentation/perf-v2/#frames-delay">Frames Delay</PlatformLink> reporting.
 
-This feature is marked as _experimental_.
-Supported in Sentry's Android SDK version `7.4.0` and above.
-
-</Alert>
-
-Performance V2 is a set of features which enrich your existing instrumentation, giving you more insights into potential performance bottlenecks. These features tightly integrate with the [Mobile Vitals](/product/insights/mobile/mobile-vitals/) insights module.
+Since version 8 of the SDK, Performance V2 is generally available and enabled by default. In versions `7.4.0..<8.0.0`, this feature is available as _experimental_ and you need to opt in to use it:
 
 ### Enabling Performance V2
 
-```java {filename:MyApplication.java}
+```java {filename:MyApplication.java} {4}
 import io.sentry.android.core.SentryAndroid;
 
 SentryAndroid.init(this, options -> {
   options.setEnablePerformanceV2(true);
 });
 ```
 
-```kotlin {filename:MyApplication.kt}
+```kotlin {filename:MyApplication.kt} {4}
 import io.sentry.android.core.SentryAndroid
 
 SentryAndroid.init(this) { options ->
   options.enablePerformanceV2 = true
 }
 ```
 
-```xml {filename:AndroidManifest.xml}
+```xml {filename:AndroidManifest.xml} {3-5}
 <manifest>
     <application>
-        <meta-data android:name="io.sentry.performance-v2.enable" android:value="true" />
+        <meta-data
+          android:name="io.sentry.performance-v2.enable"
+          android:value="true" />
     </application>
 </manifest>
 ```
 
 ### App Start
 
-Besides enabling performance-v2, this feature requires the <PlatformLink to="/configuration/gradle/">Sentry Android Gradle Plugin</PlatformLink> (version `4.2.0` or above) to be applied to your app module.
+Besides enabling Performance V2, this feature requires the <PlatformLink to="/configuration/gradle/">Sentry Android Gradle Plugin</PlatformLink> (version `4.2.0` or above) to be applied to your app module.
 
 Once enabled, your App Start transaction will show a detailed span breakdown of various components:
 * `process.load`: The process initialization time