fix accidental code comment in 1.5.6

Fixed CSS bug that hid the comment field.

1.5.5 is a very minor change, no new functionality has been added.
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- Made tab mode default for new installs.
- Cleaned up and linted code.

Fixed conflict with karaoke extension
Slight improvement with thumbnail sizing and quality

Added the ability to disable the player thumbnail.

Added setting to toggle for individual tabs.
Added an options page to configure the settings.
Tweak overlay cleanup logic.
about:addons description update

Added setting to toggle for individual tabs.
Added an options page to configure the settings.
Tweak overlay cleanup logic.

Implemented blocking of Youtube ads.
Tweaked image overlay logic.
Refined a few things in the filtering of network requests.
Mainly technical changes for a better user experience, need feedback on this version https://github.com/sheddup/YoutubeAUDIO/issues.

This version contains modified code licensed under the Mozilla Public License 2.0.
You can obtain the unmodified code here https://addons.mozilla.org/en-US/firefox/addon/youtube-adblock/versions/0.1.5 and the modified code here https://addons.mozilla.org/en-US/firefox/addon/youtubeaudio/versions/1.4