Enable more markdown paste features in textarea editor (#35494)

Enable the [same paste
features](https://github.com/github/paste-markdown#paste-markdown-objects)
that GitHub has, notably the ability to paste text containing HTML links
and have them automatically turn into Markdown links. As far as I can
tell, previous paste features all work as expected.

---------

Signed-off-by: silverwind <me@silverwind.io>

pnpm-lock.yaml

@@ -41,6 +41,9 @@ importers:
       '@github/markdown-toolbar-element':
         specifier: 2.2.3
         version: 2.2.3
+      '@github/paste-markdown':
+        specifier: 1.5.3
+        version: 1.5.3
       '@github/relative-time-element':
         specifier: 4.4.8
         version: 4.4.8
@@ -718,6 +721,9 @@ packages:
   '@github/markdown-toolbar-element@2.2.3':
     resolution: {integrity: sha512-AlquKGee+IWiAMYVB0xyHFZRMnu4n3X4HTvJHu79GiVJ1ojTukCWyxMlF5NMsecoLcBKsuBhx3QPv2vkE/zQ0A==}
 
+  '@github/paste-markdown@1.5.3':
+    resolution: {integrity: sha512-PzZ1b3PaqBzYqbT4fwKEhiORf38h2OcGp2+JdXNNM7inZ7egaSmfmhyNkQILpqWfS0AYtRS3CDq6z03eZ8yOMQ==}
+
   '@github/relative-time-element@4.4.8':
     resolution: {integrity: sha512-FSLYm6F3TSQnqHE1EMQUVVgi2XjbCvsESwwXfugHFpBnhyF1uhJOtu0Psp/BB/qqazfdkk7f5fVcu7WuXl3t8Q==}
 
@@ -5024,6 +5030,8 @@ snapshots:
 
   '@github/markdown-toolbar-element@2.2.3': {}
 
+  '@github/paste-markdown@1.5.3': {}
+
   '@github/relative-time-element@4.4.8': {}
 
   '@github/text-expander-element@2.9.2':