Snapshot: Normalize annotation whitespace

Range#toString() preserves whitespace from the HTML verbatim, which is
not what we want.

https://forums.zotero.org/discussion/115473/z7-beta-unexpected-newlines-in-sep-snapshot-annotations

src/dom/common/lib/range.ts

@@ -215,3 +215,18 @@ export function getPageRects(range: Range): DOMRectList {
 	}
 	return rects;
 }
+
+export function getInnerText(range: Range): string {
+	let doc = range.commonAncestorContainer.ownerDocument;
+	if (!doc) {
+		return range.toString();
+	}
+
+	// We need to actually insert the wrapper into the DOM to get a white-space-normalized innerText
+	let wrapper = doc.createElement('div');
+	wrapper.append(range.cloneContents());
+	doc.body.append(wrapper);
+	let innerText = wrapper.innerText;
+	wrapper.remove();
+	return innerText;
+}

src/dom/snapshot/snapshot-view.ts

@@ -8,6 +8,7 @@ import {
 	OutlineItem
 } from "../../common/types";
 import {
+	getInnerText,
 	getStartElement
 } from "../common/lib/range";
 import {
@@ -182,7 +183,7 @@ class SnapshotView extends DOMView<SnapshotViewState, SnapshotViewData> {
 		if (range.collapsed) {
 			return null;
 		}
-		let text = type == 'highlight' || type == 'underline' ? range.toString().trim() : undefined;
+		let text = type == 'highlight' || type == 'underline' ? getInnerText(range).trim() : undefined;
 		// If this annotation type wants text, but we didn't get any, abort
 		if (text === '') {
 			return null;