Add multiple links support to markdown codecs

packages/parchment/lib/src/codecs/markdown.dart

@@ -35,9 +35,7 @@ class _ParchmentMarkdownDecoder extends Converter<String, ParchmentDocument> {
     r'(`(?<inline_code_text>.+?)`)',
   );
 
-  // as per https://www.michaelperrin.fr/blog/2019/02/advanced-regular-expressions
-  static final _linkRegExp =
-      RegExp(r'\[(?<text>.+)\]\((?<url>[^ ]+)(?: "(?<title>.+)")?\)');
+  static final _linkRegExp = RegExp(r'\[([^\]]+)\]\(([^)]+)\)');
   static final _ulRegExp = RegExp(r'^( *)\* +(.*)');
   static final _olRegExp = RegExp(r'^( *)\d+[.)] +(.*)');
   static final _clRegExp = RegExp(r'^( *)- +\[( |x|X)\] +(.*)');

packages/parchment/test/codecs/markdown_test.dart

@@ -225,6 +225,23 @@ void main() {
       expect(andBack, markdown);
     });
 
+    test('double link', () {
+      final markdown =
+          'This **house** is a [circus](https://github.com) and [home](https://github.com)\n\n';
+      final document = parchmentMarkdown.decode(markdown);
+      final delta = document.toDelta();
+
+      expect(delta.elementAt(3).data, 'circus');
+      expect(delta.elementAt(3).attributes?['b'], null);
+      expect(delta.elementAt(3).attributes?['a'], 'https://github.com');
+
+      expect(delta.elementAt(5).data, 'home');
+      expect(delta.elementAt(5).attributes?['a'], 'https://github.com');
+
+      final andBack = parchmentMarkdown.encode(document);
+      expect(andBack, markdown);
+    });
+
     test('style around link', () {
       final markdown =
           'This **house** is a **[circus](https://github.com)**\n\n';