[MFM] Improve hashtag parsing

test/mfm.ts

@@ -550,6 +550,14 @@ describe('MFM', () => {
 				]);
 			});
 
+			it('ignore square brackets', () => {
+				const tokens = parse('#foo]');
+				assert.deepStrictEqual(tokens, [
+					leaf('hashtag', { hashtag: 'foo' }),
+					text(']'),
+				]);
+			});
+
 			it('allow including number', () => {
 				const tokens = parse('#foo123');
 				assert.deepStrictEqual(tokens, [