Disabling some "unused" warnings

I'd submitted code that's never actually used in the android/snippets apps. Ideally we'd include it in an app, but in the meantime, disabling the "unused" warnings.

Also removed one line (outside of a published-on-DAC code block) that turned out not to be needed.

No changes to the code that's included on DAC, and the code still compiles.

(I also see some areas where the actual code snippet is generating warnings, but I'll resolve those in separate PRs that can be reviewed by the appropriate SMEs for those docs.)

Author: asolovay

misc/src/main/java/com/example/snippets/PreloadManagerKotlinSnippets.kt

@@ -30,6 +30,7 @@ import java.lang.Math.abs
 // constants to make the code snippets work
 const val currentPlayingIndex = 10
 
+@Suppress("UNUSED_PARAMETER")
 @UnstableApi
 // [START android_defaultpreloadmanager_MyTargetPreloadStatusControl]
 class MyTargetPreloadStatusControl(
@@ -57,6 +58,7 @@ class MyTargetPreloadStatusControl(
 }
 // [END android_defaultpreloadmanager_MyTargetPreloadStatusControl]
 
+@Suppress("UNUSED_PARAMETER")
 class PreloadManagerSnippetsKotlin {
 
     class PreloadSnippetsActivity : AppCompatActivity() {
@@ -73,8 +75,6 @@ class PreloadManagerSnippetsKotlin {
             val preloadManager = preloadManagerBuilder.build()
             // [END android_defaultpreloadmanager_createPLM]
 
-            val player = preloadManagerBuilder.buildExoPlayer()
-
             // [START android_defaultpreloadmanager_addMedia]
             val initialMediaItems = pullMediaItemsFromService(/* count= */ 20)
             for (index in 0 until initialMediaItems.size) {

misc/src/main/java/com/example/snippets/backgroundwork/WakeLockSnippetsJava.java

@@ -6,6 +6,7 @@
 
 import androidx.annotation.Nullable;
 
+@SuppressWarnings("Unused")
 public class WakeLockSnippetsJava extends Activity {
 
     PowerManager.WakeLock wakeLock;
@@ -23,6 +24,7 @@ protected void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
     }
 
+    @SuppressWarnings("UNUSED")
     // [START android_backgroundwork_wakelock_release_java]
     void doSomethingAndRelease() throws MyException {
         try {

misc/src/main/java/com/example/snippets/backgroundwork/WakeLockSnippetsKotlin.kt

@@ -22,6 +22,7 @@ import android.os.Bundle
 import android.os.PowerManager
 
 // Snippets for doc page go here
+@Suppress("UNUSED_PARAMETER")
 class WakeLockSnippetsKotlin : Activity() {
 
     // [START android_backgroundwork_wakelock_create_kotlin]