Fixed gitignore and commited missing file

.gitignore

@@ -8,8 +8,8 @@ captures/
 *~
 .weblate
 *.class
-**/debug/
-**/release/
+app/debug/
+app/release/
 
 # vscode / eclipse files
 *.classpath

app/src/debug/java/org/schabi/newpipe/settings/DebugSettingsBVLeakCanary.java

@@ -0,0 +1,15 @@
+package org.schabi.newpipe.settings;
+
+import android.content.Intent;
+
+import leakcanary.LeakCanary;
+
+@SuppressWarnings("unused") // Class is used but loaded via reflection
+public class DebugSettingsBVLeakCanary
+        implements DebugSettingsFragment.DebugSettingsBVLeakCanaryAPI {
+
+    @Override
+    public Intent getNewLeakDisplayActivityIntent() {
+        return LeakCanary.INSTANCE.newLeakDisplayActivityIntent();
+    }
+}