Handle default string % literal for Ruby

Another ruby syntax thing

```ruby
  %{Hello World} == %q{Hello World}
````

One gotcha though:

```ruby
  5%(2) == 5 % 2
```
Will be seen as a string, but it will be interpreted
as the modulo operator by ruby.

But It's not easy to fix it, and as far as I know, there is no editor that handle that edge case.