rewrite array builtins in zern

examples/brainfuck.zr

@@ -1,4 +1,5 @@
 func main[] : I64
+    // https://brainfuck.org/sierpinski.b
     let src: String = "++++++++[>+>++++<<-]>++>>+<[-[>>+<<-]+>>]>+[-<<<[->[+[-]+>++>>>-<<]<[<]>>++++++[<<+++++>>-]+<<++.[-]<<]>.>+[>>]>+]"
     let src_len: I64 = strlen(src)
     let i: I64 = 0

examples/quicksort.zr

@@ -1,7 +1,7 @@
-func quicksort[arr: Array] : I64
+func quicksort[arr: Array] : Void
     do_quicksort(arr, 0, Array.size(arr)-1)
 
-func do_quicksort[arr: Array, low: I64, high: I64] : I64
+func do_quicksort[arr: Array, low: I64, high: I64] : Void
     if low < high
         let i: I64 = partition(arr, low, high)
         do_quicksort(arr, low, i - 1)

examples/tcp_client.zr

@@ -9,7 +9,7 @@ func main[] : I64
     String.set(sa, 1, 0)
     String.set(sa, 2, Bit.rshift(port, 8) && 255)
     String.set(sa, 3, port && 255)
-    // 23.192.228.80
+    // 23.192.228.80 (example.com)
     String.set(sa, 4, 23)
     String.set(sa, 5, 192)
     String.set(sa, 6, 228)