Add test that %0 is kept

Co-authored-by: Carl Christian Snethlage <[email protected]>

src/test/java/org/jabref/logic/l10n/LocalizationTest.java

@@ -70,4 +70,10 @@ void unknownTranslation() {
     void unsetLanguageTranslation() {
         assertEquals("Groups", Localization.lang("Groups"));
     }
+
+    @Test
+    void placeholderIsKeptWhenNoParameter() {
+        // This behavior is required when %0 should be transformed to a hyperlink in the UI.
+        assertEquals("Groups %0", Localization.lang("Groups %0"));
+    }
 }