Minor update to “Hello Worlds”

Augie “durin42” Fackler and Colin Barrett contributed some info worth adding to “Hello Worlds, cut four ways.

durin42 complained that he doesn't like multiple return statements in a function. the version shown in the page under his name is what I showed him as an alternative, and he approved. I then came up with a third implementation based on the second.

Colin pointed out a couple of reasons why the Shortest Possible Hello World was not, in fact, the Shortest Possible Hello World. I fixed 'em both, and there should be no further ways to make it shorter.

with this update, the version on the page becomes 0.2. thanks to both of you for the pointers. ☺