[atomics.ref.float] Fix typo

Author: tkoeppe

source/threads.tex

@@ -3942,8 +3942,8 @@
                                    memory_order = memory_order::seq_cst) const noexcept;
     constexpr value_type fetch_fmaximum(value_type,
                                         memory_order = memory_order::seq_cst) const noexcept;
-    constexpr valu_type fetch_fminimum(value_type,
-                                       memory_order = memory_order::seq_cst) const noexcept;
+    constexpr value_type fetch_fminimum(value_type,
+                                        memory_order = memory_order::seq_cst) const noexcept;
     constexpr value_type fetch_fmaximum_num(value_type,
                                             memory_order = memory_order::seq_cst) const noexcept;
     constexpr value_type fetch_fminimum_num(value_type,