Update/Fix SA and update /info accordingly

[Pikefish]

Sign Artist is pretty great but the text generation function isn't working very well, and the /info page about it is incorrect.
/info advises that you should enter /sil 'hello world' to write hello world on a sign, but that produces no result, the text generator is actually called with the command /silt instead.

I've done some diagnostics using a small wooden sign. Entering /silt 'hello world' results in the sign displaying 'hello and /silt hello world produces hello whereas /silt hello produces nothing. /silt "hello world" also produces nothing. Conclusion: its parsing is well borked. Multiple words results in only the first word working unless it begins with ", while /info suggested it was ' style quotations that it would be paying attention to.

I understand SA is a plugin developed by Whispers88 and as such the issue might not be within your power to fix, but it might also be your command parsing before the signText call, or maybe it just needs updating, there was one published 3 months ago.