[Bugfix] #368: Extend supported lyrics tags

[michilyy]

What kind of change does this PR introduce? (check at least one)

• [x] Bugfix
• [ ] Feature
• [ ] Code style update
• [ ] Refactor
• [ ] Build-related changes
• [ ] Other, please describe:

The PR fulfills these requirements:

• [x] When resolving a specific issue, it's referenced in the PR's title (e.g. fix #xxx[,#xxx], where "xxx" is the issue number)

If adding a new feature, the PR's description includes:

• [ ] A convincing reason for adding this feature (it's best to open a suggestion issue first and wait for approval before working on it)

Other information: Different file use different names for lyrics. Swingmusic currently only searches for the tag lyrics. This change now searches for any lyrics tag provided in lyrics_tag

lyrics_tag = {"lyrics", "unsyncedlyrics", "sylt", "uslt"}