Add notes on how to enable VERBOSE

Otherwise it can be challenging to find instructions
on how to enable verbose logs on devices.
This will save time for many new engineers.

Test: n/a
Change-Id: I1d814247c26d65cd6057ea438a84790c82eee83d
diff --git a/include/android-base/logging.h b/include/android-base/logging.h
index 9064075..179ddf0 100644
--- a/include/android-base/logging.h
+++ b/include/android-base/logging.h
@@ -27,6 +27,8 @@
 //   LOG(INFO) << "Some text; " << some_value;
 //
 // Replace `INFO` with any severity from `enum LogSeverity`.
+// Most devices filter out VERBOSE logs by default, run
+// `adb shell setprop log.tag.<TAG> V` to see them in adb logcat.
 //
 // To log the result of a failed function and include the string
 // representation of `errno` at the end: