Support a sigil for safe HTML

[the-mikedavis]

EEx has a sigil for doing safe HTML in your Elixir code. At first look it doesn't seem to be too interesting, but with the new LiveView coming up, it looks pretty useful.

I hate writing Eex, love writing Slime. It'd be cool to be able to write slime in the live view, and it seems to me like a sigil for this is the first step in the right direction.

(Feature request)

[doomspork]

@the-mikedavis would you be open to taking a first stab at this? We'd welcome a PR 😁

[the-mikedavis]

@doomspork Sure thing. I have one nagging question, though. What should the sigil be? ~S is already used pretty commonly. Either we override ~S or we choose another character like L or H. What are your thoughts on this?

[doomspork]

That's a good question @the-mikedavis 🤔. @Rakoth do you have any preference? I'm leaning towards L.