Update ffprobe_media_tests.rs

tests/ffprobe_media_tests.rs

@@ -7,6 +7,11 @@ use std::io::Read;
 
 use bwavfile::WaveReader;
 
+// Media Tests
+//
+// These tests compare metadata and format data read by ffprobe with the same values
+// as read by `WaveReader`.
+
 // This seems rickety but we're going with it
 fn assert_match_stream<T>(stream_key: &str, 
                     other: impl Fn(&mut WaveReader<File>) -> T)