Improve OG description parsing about zine

[kiyov09]

@Folyd
I'm interested in this one too. I want to start helping on the rust side of things.

[Folyd]

Wow, thanks. To help you get started: the extract_description() function is the point we need to improve and find_map() is the culprit of this issue.

zine/src/markdown/mod.rs

Lines 7 to 32 in e64a501

	/// Extract the description from markdown content.
	///
	/// The strategy is extract the first meaningful line,
	/// and only take at most 200 plain chars from this line.
	pub fn extract_description(markdown: &str) -> String {
	markdown
	.lines()
	.find_map(|line| {
	// Ignore heading, image line.
	let line = line.trim();
	if line.is_empty() || line.starts_with(['#', '!']) {
	None
	} else {
	let raw = strip_markdown(line);
	// If the stripped raw text is empty, we step to next one.
	if raw == "\n" || raw.is_empty() {
	None
	} else {
	// No more than 200 chars.
	// Also, replace double quote to single quote.
	Some(raw.chars().take(200).collect::<String>().replace('"', "'"))
	}
	}
	})
	.unwrap_or_default()
	}

[kiyov09]

Yeap. I was taking a look at that function previously. It works fine but only returns up to 200 chars of the first meaningful line.
In this case "Dear Rustaceans," is the whole line.
What do you think should be the new behavior?

[Folyd]

I don't think the first meaningful line is enough, such as in this case. The better approach is to extract at most 200 chars no matter how many lines.

[Folyd]

Close via #170.