demux: mkv: fix formatting of debug info

Before:

[00007639bc0047a0] mkv demux debug: |   + Seek head
[00007639bc0047a0] mkv demux debug: |   - info at 213
[00007639bc0047a0] mkv demux debug: |   + Information
[00007639bc0047a0] mkv demux debug: |   |   + TimecodeScale=1000000
[00007639bc0047a0] mkv demux debug: |   |   + Muxing Application=Lavf61.7.100
[00007639bc0047a0] mkv demux debug: |   |   + Writing Application=Lavf61.7.100
[00007639bc0047a0] mkv demux debug: |   |   + UID=26af75836a3623c2
[00007639bc0047a0] mkv demux debug: |   |   + Duration=144900
[00007639bc0047a0] mkv demux debug: |   - tracks at 291
[00007639bc0047a0] mkv demux debug: |   + Tracks
[00007639bc0047a0] mkv demux debug: |   |   + Track Entry
[00007639bc0047a0] mkv demux debug: |   |   |   + Track Number=1
[00007639bc0047a0] mkv demux debug: |   |   |   + Track UID=347649eb
[00007639bc0047a0] mkv demux debug: |   |   |   + Track Lacing=0
[00007639bc0047a0] mkv demux debug: |   |   |   + Track Language=`eng'
[00007639bc0047a0] mkv demux debug: |   |   |   + Track Default=0
[00007639bc0047a0] mkv demux debug: |   |   |   + Track Codec Delay =8937   <-------------------------
[00007639bc0047a0] mkv demux debug: |   |   |   + Track Type=audio
[00007639bc0047a0] mkv demux debug: |   |   |   + Track CodecId=A_MS/ACM
[00007639bc0047a0] mkv demux debug: |   |   |   + Track Audio
[00007639bc0047a0] mkv demux debug: |   |   |   |   + achan=2
[00007639bc0047a0] mkv demux debug: |   |   |   |   + afreq=16000
[00007639bc0047a0] mkv demux debug: |   |   |   |   + abits=16
[00007639bc0047a0] mkv demux debug: |   |   |   + Track Max BlockAdditionID=0
[00007639bc0047a0] mkv demux debug: |   |   |   + Track CodecPrivate size=98
[00007639bc0047a0] mkv demux debug: |   - tags at 482
[00007639bc0047a0] mkv demux debug: |   + Tags

after:

[000074fde8c02240] mkv demux debug: |   + Seek head
[000074fde8c02240] mkv demux debug: |   - info at 213
[000074fde8c02240] mkv demux debug: |   + Information
[000074fde8c02240] mkv demux debug: |   |   + TimecodeScale=1000000
[000074fde8c02240] mkv demux debug: |   |   + Muxing Application=Lavf61.7.100
[000074fde8c02240] mkv demux debug: |   |   + Writing Application=Lavf61.7.100
[000074fde8c02240] mkv demux debug: |   |   + UID=bf6fd95de33a7a4c
[000074fde8c02240] mkv demux debug: |   |   + Duration=144900
[000074fde8c02240] mkv demux debug: |   - tracks at 291
[000074fde8c02240] mkv demux debug: |   + Tracks
[000074fde8c02240] mkv demux debug: |   |   + Track Entry
[000074fde8c02240] mkv demux debug: |   |   |   + Track Number=1
[000074fde8c02240] mkv demux debug: |   |   |   + Track UID=47c9256d
[000074fde8c02240] mkv demux debug: |   |   |   + Track Lacing=0
[000074fde8c02240] mkv demux debug: |   |   |   + Track Language=`eng'
[000074fde8c02240] mkv demux debug: |   |   |   + Track Default=0
[000074fde8c02240] mkv demux debug: |   |   |   + Track Codec Delay=10906 <---------------------
[000074fde8c02240] mkv demux debug: |   |   |   + Track Type=audio
[000074fde8c02240] mkv demux debug: |   |   |   + Track CodecId=A_MS/ACM
[000074fde8c02240] mkv demux debug: |   |   |   + Track Audio
[000074fde8c02240] mkv demux debug: |   |   |   |   + achan=2
[000074fde8c02240] mkv demux debug: |   |   |   |   + afreq=32000
[000074fde8c02240] mkv demux debug: |   |   |   |   + abits=16
[000074fde8c02240] mkv demux debug: |   |   |   + Track Max BlockAdditionID=0
[000074fde8c02240] mkv demux debug: |   |   |   + Track CodecPrivate size=98
[000074fde8c02240] mkv demux debug: |   - tags at 482
[000074fde8c02240] mkv demux debug: |   + Tags