Avoid fully empty links in test suite

Typst complains about those.

Author: tarleb

test/testsuite.native

@@ -365,7 +365,6 @@ Pandoc (Meta {unMeta = fromList [("author",MetaList [MetaInlines [Str "John",Spa
 ,Para [Link ("",[],[]) [Str "URL",Space,Str "and",Space,Str "title"] ("/url/","title with single quotes")]
 ,Para [Link ("",[],[]) [Str "with_underscore"] ("/url/with_underscore","")]
 ,Para [Link ("",[],[]) [Str "Email",Space,Str "link"] ("mailto:nobody@nowhere.net","")]
-,Para [Link ("",[],[]) [Str "Empty"] ("",""),Str "."]
 ,Header 2 ("reference",[],[]) [Str "Reference"]
 ,Para [Str "Foo",Space,Link ("",[],[]) [Str "bar"] ("/url/",""),Str "."]
 ,Para [Str "With",Space,Link ("",[],[]) [Str "embedded",Space,Str "[brackets]"] ("/url/",""),Str "."]