Syntax and docs corrections

Author: ckormanyos

README.md

@@ -45,7 +45,7 @@ Wide-decimal is written in header-only C++14, and compatible through C++14, 17,
   - Relatively wide precision range from about ${\sim}~10 {\ldots} 10^{7}$ decimal digits.
   - Moderately good efficiency over the entire wide precision range.
   - Clean header-only C++14 design.
-  - Seamless portability to any modern C++20, 23 compiler and beyond.
+  - Seamless portability to any modern C++14, 17, 20, 23 compiler and beyond.
   - Scalability with small memory footprint and efficiency suitable for both PC/workstation systems as well as _bare-metal_ embedded systems.
 
 ## Quick start

util/memory/util_n_slot_array_allocator.h

@@ -150,9 +150,9 @@
     }
 
   private:
-    static slot_array_memory_type& slot_array_memory() { static slot_array_memory_type my_mem_instance; return my_mem_instance; }
-    static slot_array_flags_type&  slot_flags       () { static slot_array_flags_type  my_flg_instance; return my_flg_instance; }
-    static std::size_t&            slot_max_index   () { static std::size_t            my_idx_instance; return my_idx_instance; }
+    static auto slot_array_memory() -> slot_array_memory_type& { static slot_array_memory_type my_mem_instance; return my_mem_instance; }
+    static auto slot_flags       () -> slot_array_flags_type&  { static slot_array_flags_type  my_flg_instance; return my_flg_instance; }
+    static auto slot_max_index   () -> std::size_t&            { static std::size_t            my_idx_instance; return my_idx_instance; }
   };
 
   // Global comparison operators (required by the standard).