[fs.filesystem.syn] fix ordering of exists and equivalent

Author: jwakely

source/iostreams.tex

@@ -10213,13 +10213,13 @@
   void current_path(const path& p);
   void current_path(const path& p, error_code& ec) noexcept;
 
+  bool equivalent(const path& p1, const path& p2);
+  bool equivalent(const path& p1, const path& p2, error_code& ec) noexcept;
+
   bool exists(file_status s) noexcept;
   bool exists(const path& p);
   bool exists(const path& p, error_code& ec) noexcept;
 
-  bool equivalent(const path& p1, const path& p2);
-  bool equivalent(const path& p1, const path& p2, error_code& ec) noexcept;
-
   uintmax_t file_size(const path& p);
   uintmax_t file_size(const path& p, error_code& ec) noexcept;