Incomprehensible example for `packed` encoding

[tvogel]

Since 1c34706, the examples for packed encoding in

protocolbuffers.github.io/content/programming-guides/encoding.md

Line 327 in c5d2eda

`1`, `2`, and `3`, this *could* be encoded as `` `3206038e029ea705` ``, or

make no sense (to me):

1. The "hello" string is not contained in the encoded bytes (in contrast to before the mentioned commit).
2. The numbers 3 270 86942 in the protoscope representations have no connection to the claimed "1, 2 and 3.