Feature request: use links to srt files

[hornhaut]

Maybe I just could not find it, but it would be handy to be able to link to the srt file containing the "lyrics" instead of pasting it manually. I use it for recordings of interviews and after transcribing the audio file using whisper I have srt files. Might look like this:

```lrc
source [[audio_file.mp3]]
lyrics [[my_transcript.srt]]

Thanks for the plugin so far, it already is great  :)

[voltel]

I also noticed that when placing the ```lrc codeblock into a callout, the player is not visible after the sentence at a bottom of a visible screen is scrolled past. Which also suggests that the sentences should not be defined in th same block where the player source is declared. This will give the capability to link different srt files to the same mp3 (e.g., providing subtitles in different languages).

E.g.

```lrc
player: id_1
source: [[audio_file.mp3]]

[!INFO]- Transcript in the language of an audio

player: id_1
lyrics: [[my_transcript.srt]]

[!INFO]- Subtitles in another language

player: id_1
lyrics: [[subtitles_lang_one.srt]]