Fix "hello" string memory breakdown

Author: martosaur

chapters/type_system.asciidoc

@@ -430,7 +430,7 @@ The string "hello" might then look like this in memory (xref:string_representati
          128 |00000000 00000000 00000110 10001111| (h) 104 bsl 4 + small int tag <--+  |
          124 |00000000 00000000 00000000 01110001| 112 + list tag  --------------------|--+
          120 |00000000 00000000 00000110 01011111| (e) 101 bsl 4 + small int tag <-----+  |
-         116 |00000000 00000000 00000000 01110001| 112 + list tag  -----------------------|--+
+         116 |00000000 00000000 00000000 01110001| 104 + list tag  -----------------------|--+
          112 |00000000 00000000 00000110 11001111| (l) 108 bsl 4 + small int tag <--------+  |
          108 |00000000 00000000 00000000 01110001| 96 + list tag  ---------------------------|--+
          104 |00000000 00000000 00000110 11001111| (l) 108 bsl 4 + small int tag <-----------+  |