[optional.syn] Fix indentation (cplusplus#9018)

Author: Andreas-Krug

source/utilities.tex

@@ -3577,7 +3577,7 @@
   template<class T, class U> constexpr bool operator>=(const optional<T>&, const U&);
   template<class T, class U> constexpr bool operator>=(const T&, const optional<U>&);
   template<class T, class U>
-      requires (!@\exposconcept{is-derived-from-optional}@<U>) && @\libconcept{three_way_comparable_with}@<T, U>
+    requires (!@\exposconcept{is-derived-from-optional}@<U>) && @\libconcept{three_way_comparable_with}@<T, U>
     constexpr compare_three_way_result_t<T, U>
       operator<=>(const optional<T>&, const U&);