Go Caveats

I don’t particularly love that this isn’t the cleanest set of warnings in the world, but the combination of Homebrew, zsh & Go seems to really screw up the setting of the GOPATH & the $PATH as recommended. (*The problem seems to replicate across any non-default shell*). I’ve chucked in a few lines consequently about how to handle non-default shells.

I’ll respect if this somewhat cumbersome explanation is rejected, but hopefully it’s useful to include.
That's expected behaviour; bash will do the same thing. `export` only sets the scope for the current shell rather than setting it across shells.