ZSH packaging helper instructions don't work

[EbonJaeger]

Following the instructions here to install the Solus packaging helper functions does not result in the functions being usable.

I don't know the correct way to do it, not being familiar with ZSH. @Staudey has the following in his .zshrc file:

# This works
#for file in $HOME/.zshrc.d/*.zsh; do
#    . "$file"
#done

# This doesn't, why?
fpath=(~/.zshrc.d $fpath)
# Unless I add this and execute "solus-monorepo-helpers.zsh" first, which is weird
autoload -Uz solus-monorepo-helpers.zsh
solus-monorepo-helpers.zsh
# This also doesn't help:
# autoload -Uz ${fpath[1]}/*(:t)

[TraceyC77]

I found the instructions for bash didn't work either. Fixing both.