Add JUnit LoggerExtension documentation

Author: absurdlylongusername

extractor/src/test/java/org/schabi/newpipe/extractor/LoggerExtension.java

@@ -4,6 +4,13 @@
 import org.junit.jupiter.api.extension.ExtensionContext;
 import org.schabi.newpipe.extractor.utils.ExtractorLogger;
 
+/**
+ * JUnit extension class for globally setting up the logger for all extractor tests<br>
+ * See <a href="https://www.baeldung.com/junit-5-extensions#1-automatic-extension-registration">here</a> on how this works
+ * <br>
+ * To disable this, set {@code junit.jupiter.extensions.autodetection.enabled = false}
+ * in junit-platform.properties
+ */
 public class LoggerExtension implements BeforeAllCallback {
     private static boolean set = false;
 

extractor/src/test/java/org/schabi/newpipe/extractor/utils/ExtractorLoggerTest.java

@@ -5,6 +5,9 @@
 
 import static org.junit.jupiter.api.Assertions.*;
 
+/**
+ * See {@link org.schabi.newpipe.extractor.LoggerExtension} for how global logging is set up for tests
+ */
 class ExtractorLoggerTest {
 
     private CapturingLogger logger;