LinkReferenceDefinition takes over sourceSpans from a block following it

[obask]

Steps to reproduce the problem (provide example Markdown if applicable):

Run this example with IncludeSourceSpans.BLOCKS https://spec.commonmark.org/0.31.2/#example-210

import org.commonmark.node.Node;
import org.commonmark.parser.IncludeSourceSpans;
import org.commonmark.parser.Parser;

public class Main {
    public static void main(String[] args) {
        Parser parser = Parser.builder().includeSourceSpans(IncludeSourceSpans.BLOCKS).build();
        String input = "[foo]: /url\n\"title\" ok";
        Node node = parser.parse(input);
        System.out.println("LinkReferenceDefinition spans: " + node.getFirstChild().getSourceSpans());
        System.out.println("Paragraph(last child)   spans: " + node.getLastChild().getSourceSpans());
    }
}

Expected behavior:

It should assign source spans to blocks

LinkReferenceDefinition spans: []
Paragraph(last child)   spans: [SourceSpan{line=1, column=0, length=10}]

Actual behavior:

It only assigns source spans to a LinkReferenceDefinition which is not a block

LinkReferenceDefinition spans: [SourceSpan{line=0, column=0, length=11}, SourceSpan{line=1, column=0, length=10}]
Paragraph(last child)   spans: []

PS [unrelated] a top level Document should probably only contain Blocks while LinkReferenceDefinition is a Node

[robinst]

Thanks! Raised a PR to fix this.

PS [unrelated] a top level Document should probably only contain Blocks while LinkReferenceDefinition is a Node

Link reference definitions are a bit of an odd one in the way they're parsed. But in the spec, they're listed under blocks: https://spec.commonmark.org/0.31.2/#link-reference-definitions

We should probably change them to extends Block instead of extends Node. Thoughts? I made the change and none of the tests break, but it's technically an API change.

[robinst]

We should probably change them to extends Block instead of extends Node. Thoughts? I made the change and none of the tests break, but it's technically an API change.

Done in 3038d47