List of changes:
1. Rename `signfs` to `scale`, to better match what it actually does
(force --sub-scale to apply to ASS subtitles), and fix the blatantly
wrong documentation (it actually specifically does *not* apply to
signs)
2. Rename `--sub-ass-style-override` to `--sub-ass-override` to help
reduce confusion between it and `--sub-ass-force-style`, as well as
pointing out that it doesn't necessarily actually override styles.
(The new `scale` option, for example, only sets
ASS_OVERRIDE_BIT_FONT_SIZE, but not ASS_OVERRIDE_BIT_STYLE)
3. Mention that `--sub-ass-override` is generally sort of smart about
only overriding dialog, not signs.
Niklas Haas
4d1ffecabc