[red-knot] `reveal_type` should display raw characters

[dhruvmanila]

Looking at something like:

from typing import Literal, reveal_type

x: Literal["\n"] = "\n"

reveal_type(x)

We get:

red-knot: Revealed type is `Literal["
  "]` [revealed-type]
Pyright: Type of "e" is "Literal['\n']"
mypy: Revealed type is "Literal['\n']"

I think it would be useful to not render the characters and instead display it as raw instead similar to Pyright and mypy.

[MichaReiser]

We could try using https://doc.rust-lang.org/std/primitive.str.html#method.escape_debug when displaying Literal