Do not fill blanks to align if there is only one line.

include/spdlog/fmt/bin_to_hex.h

@@ -176,6 +176,8 @@ struct formatter<spdlog::details::dump_info<T>>
             *inserter++ = hex_chars[ch & 0x0f];
         }
         if (show_ascii)
+        {
+            if (the_range.end() - the_range.begin() > size_per_line)
             {
                 auto blank_num = size_per_line - (the_range.end() - start_of_line);
                 while (blank_num-- > 0)
@@ -187,6 +189,7 @@ struct formatter<spdlog::details::dump_info<T>>
                         *inserter++ = ' ';
                     }
                 }
+            }
             *inserter++ = ' ';
             *inserter++ = ' ';
             for (auto j = start_of_line; j != the_range.end(); j++)