[doc] logging: explain how to enable it in junit tests

base/android/java/src/org/chromium/base/Log.java

Index: base/android/java/src/org/chromium/base/Log.java
diff --git a/base/android/java/src/org/chromium/base/Log.java b/base/android/java/src/org/chromium/base/Log.java
index 7160f0e4cb4f551fbd13457737eaf3d66c7e50fe..8815e631346a98d0893b26edc62a0865309818f5 100644
--- a/base/android/java/src/org/chromium/base/Log.java
+++ b/base/android/java/src/org/chromium/base/Log.java
@@ -17,7 +17,7 @@
  * the origin of logs, and enable or disable logging in different parts of the code.
  * </p>
  * <p>
- * Usage documentation: {@code //docs/logging.md}.
+ * Usage documentation: {@code //docs/android_logging.md}.
  * </p>
  */
 public class Log {