extensions/markdown-language-features/src/languageFeatures/pathCompletions.ts/MdPathCompletionProvider/provideHeaderSuggestions
class MdPathCompletionProvider:	private async *provideHeaderSuggestions(document: SkinnyTextDocument, position: vscode.Position, context: CompletionContext, insertionRange: vscode.Range): AsyncIterable<vscode.CompletionItem> {
		const toc = await TableOfContents.createForDocumentOrNotebook(this.engine, document);
		for (const entry of toc.entries) {
			const replacementRange = new vscode.Range(insertionRange.start, position.translate({ characterDelta: context.linkSuffix.length }));
			yield {
				kind: vscode.CompletionItemKind.Reference,
				label: '#' + decodeURIComponent(entry.slug.value),
				range: {
					inserting: insertionRange,
					replacing: replacementRange,
				},
			};
		}
	}