[complex.syn] Fix indentation (#7543)

Author: Andreas-Krug

source/numerics.tex

@@ -307,14 +307,14 @@
 
   // \ref{complex.literals}, complex literals
   inline namespace literals {
-  inline namespace complex_literals {
-    constexpr complex<long double> operator""il(long double);
-    constexpr complex<long double> operator""il(unsigned long long);
-    constexpr complex<double> operator""i(long double);
-    constexpr complex<double> operator""i(unsigned long long);
-    constexpr complex<float> operator""if(long double);
-    constexpr complex<float> operator""if(unsigned long long);
-  }
+    inline namespace complex_literals {
+      constexpr complex<long double> operator""il(long double);
+      constexpr complex<long double> operator""il(unsigned long long);
+      constexpr complex<double> operator""i(long double);
+      constexpr complex<double> operator""i(unsigned long long);
+      constexpr complex<float> operator""if(long double);
+      constexpr complex<float> operator""if(unsigned long long);
+    }
   }
 }
 \end{codeblock}