Remove outdated comment in mdbook-markdown

I missed this in #2844.

Author: ehuss

crates/mdbook-markdown/src/lib.rs

@@ -4,10 +4,6 @@
 //! [mdBook](https://rust-lang.github.io/mdBook/). The [`pulldown_cmark`]
 //! crate is used as the underlying parser. This crate re-exports
 //! [`pulldown_cmark`] so that you can access its types.
-//!
-//! The parser in this library adds several modifications to the
-//! [`pulldown_cmark`] event stream. For example, it adjusts some links,
-//! modifies the behavior of footnotes, and adds various HTML wrappers.
 
 use pulldown_cmark::{Options, Parser};