Fix #4034 (#4037)

* Fix #4034

* improve

src/mfm/html.ts

@@ -157,7 +157,7 @@ export default (tokens: MfmForest, mentionedRemoteUsers: INote['mentionedRemoteU
 
 		text(token) {
 			const el = doc.createElement('span');
-			const nodes = (token.node.props.text as string).split('\n').map(x => doc.createTextNode(x));
+			const nodes = (token.node.props.text as string).split(/\r\n|\r|\n/).map(x => doc.createTextNode(x));
 
 			for (const x of intersperse('br', nodes)) {
 				el.appendChild(x === 'br' ? doc.createElement('br') : x);

test/mfm.ts

@@ -1096,6 +1096,12 @@ describe('MFM', () => {
 			const output = '<p><span>foo<br>bar<br>baz</span></p>';
 			assert.equal(toHtml(analyze(input)), output);
 		});
+
+		it('br alt', () => {
+			const input = 'foo\r\nbar\rbaz';
+			const output = '<p><span>foo<br>bar<br>baz</span></p>';
+			assert.equal(toHtml(analyze(input)), output);
+		});
 	});
 
 	it('code block with quote', () => {