Function render_warnings 

pub fn render_warnings(warnings: &[Warning<'_>], style: Style) -> String

Render the deprecations a command line used, the way a user should read them.

One line each, in the order they were collected, with the same colour vocabulary as a failure: what the user typed in yellow, what to use instead in green. The wording itself comes from crate::warn, so the plain and coloured halves cannot drift apart.