FontCollector \fn0 special case

[moi15moi]

Libass and VSFilter has a special condition with the tag \fn0

• https://sourceforge.net/p/guliverkli2/code/HEAD/tree/src/subtitles/RTS.cpp#l1683
• https://github.com/libass/libass/blob/5f57443f1784434fe8961275da08be6d6febc688/libass/ass_parse.c#L514

It is handled like \fn.

So, it should not try to search the font named 0.

Updating font cache
Parsing file
Searching for font files
Could not find font '0'
Used on lines: 1

Done

One font could not be found