bug(schemars_derive/docs): newlines get stripped in example blocks

use schemars::JsonSchema;
use serde::Deserialize;

/// # Some Config
/// 
/// This config does some stuff.
///
/// # Example
///
/// ```jsonc
/// {
///   // use this config setting in a certain way
///   "foo": ["bar", "baz"],
/// }
/// ```
#[derive(Debug, Deserialize, Default, JSONSchema)]
pub struct Config {
    foo: Vec<String>
}

When rendered to a JSON schema, the code block in the schema's description field will be stripped, causing invalid JSONC to be rendered. It looks like other markdown in description has its whitespace preserved.

GREsau / schemars

bug(schemars_derive/docs): newlines get stripped in example blocks #313