rustdoc: Strip empty line(s) above and/or below hidden code in Rust code blocks

[Havvy]

Consider the following code:

//! Top-level documentation.
//!
//! ```rust
//! // ... some Rust code ...
//!
//! # // ... hidden boilerplate-y Rust code ...
//!
//! // ... some Rust code ...
//! ```

Currently (last checked: 2024), rustdoc renders two empty lines in between the first & the last comment (quite reasonably so). However, it might be nice to essentially collapse them into a single line since the author likely didn't intend to have extra lines in the rendered output but only in the source code for legibility (since there the #-prefixed code is obviously visible).

The "workaround" / user fix for this is to manually hide the "blank" lines with #:

//! Top-level documentation.
//!
//! ```rust
//! // ... some Rust code ...
//! #
//! # // ... hidden boilerplate-y Rust code ...
//!
//! // ... some Rust code ...
//! ```

An argument could be made that this is less "esthetically pleasing" and a bit annoying.

Original issue description from 2018 for context

Basically, I want:

rust code

# secret boilerplatey rust code

more rust code

to render the same as:

rust code
#
# secret boilerplatey rust code

more rust code