String encapsulation for improved translation

I've talked it over with a translator friend. She says she prefers `{variable}` on account of liking words, but says `%0` shouldn't pose a problem. She also pointed out that `$1` might be mistakenly (albeit very unlikely) translated to €0.8.

Anyway, I'm on board with `%0`. What do you think, a regexp along these lines? Rationale: more than 10 variables in one string sounds a bit like madness and maybe you want a way to escape it.

```lua
[^\\]%[0-9]
```