Improve Rust lifetime & attribute syntax highlighting

@dobkeratops:
> if you display rust code in geany it shows the pointer lifetimes as error strings

This fixes the error string highlighting from an unmatched `'` quote char, e.g.:
```rust
pub fn explore() -> &'static str { "world" }
```
This is just a workaround, so `"world"` doesn't get lexed as a string, only as the default style. But this is much less awkward than lexing as `string_eol` with a pink background for the remainder of the line.

See also: https://github.com/geany/geany/pull/165#issuecomment-24584521

This also tweaks attribute highlighting to stop at the first space. Also a workaround.