Trim empty first lines of a code block

[PhalanxHead]

Basically, when I use a code snippet like below, that I've likely pasted in from another document:

<pre>
<code>
fn main() {
    println!("Hello World"!);
}
</code>
</pre>

Line 1 (using hljs.initLineNumbersOnLoad();) will always be blank, as it registers the line break after the <code> tag as a new line.

It's easy enough to fix, it's just a little annoying.

Describe the solution you'd like
Optionally remove the first line from the code block if it's empty.

Describe alternatives you've considered
Technically you can do this:

<pre>
<code>fn main() {
    println!("Hello World"!);
}
</code>
</pre>

But it looks a little gross to me idk.

Not a high priority by any means, but I think it would feel nice :)

[wcoder]

It's the default behavior, more details: jekyll/jekyll-help#191

Whitespace inside <pre> elements is always respected by the browser, and output as-is. A newline is treated the same as any other whitespace character.