fix detail

Signed-off-by: martinvuyk <[email protected]>

stdlib/src/builtin/string.mojo

@@ -2377,11 +2377,10 @@ struct String(
                     curr_ptr[0] = 0xFF
                 else:
                     num_bytes = 4
-                    alias bit_over_32 = 0x1_00_00
                     alias low_10b = 0b0011_1111_1111  # get lower 10 bits
                     var c2 = int(values.unsafe_get(values_idx + 1))
                     var value = ((int(c) & low_10b) << 10) | (c2 & low_10b)
-                    var unicode = bit_over_32 + value
+                    var unicode = 2**16 + value
                     curr_ptr[0] = UInt8(0xF0 | (unicode >> 18))
                     curr_ptr[1] = UInt8(c_byte | ((unicode >> 12) & low_6b))
                     curr_ptr[2] = UInt8(c_byte | ((unicode >> 6) & low_6b))