modernize: raw string literals

src/Config.h

@@ -53,9 +53,9 @@ namespace strings {
 const QString url_html = "<a href=\"\\1\">\\1</a>";
 const QRegularExpression url_regex(
   // match an URL, that is not quoted, i.e.
-  // vvvvvvv match quote via negative lookahead/lookbehind                                 vvvvvv
-  //        vvvv atomic match url -> fail if there is a " before or after                vv
-  "(?<!\")(?>((www\\.(?!\\.)|[a-z][a-z0-9+.-]*://)[^\\s<>'\"]+[^!,\\.\\s<>'\"\\]\\)\\:]))(?!\")");
+  // vvvvvv match quote via negative lookahead/lookbehind                    vv
+  //       vvvv atomic match url -> fail if there is a " before or after          vvv
+  R"((?<!")(?>((www\.(?!\.)|[a-z][a-z0-9+.-]*://)[^\s<>'"]+[^!,\.\s<>'"\]\)\:]))(?!"))");
 }
 
 // Window geometry.