docs: improve documentation on hooks and inflections

[jclusso]

For the life of me, I can't figure out where usage of hooks go when working with them directly. A proper example would be greatly helpful here. If they belong in the initializer or a config. I figured it would be nice to have a hooks.rb file in the config folder, but I was unsuccessful in getting that to work.

https://github.com/bridgetownrb/bridgetown/blob/6ff7de5fa3de68af9ebf9221e79378a7bc144459/bridgetown-website/src/_docs/plugins/hooks.md?plain=1#L24-L28

This also leads me to having no idea how to get inflections to work. I think a full example showing where and what hook it should use would be great.

https://github.com/bridgetownrb/bridgetown/blob/6ff7de5fa3de68af9ebf9221e79378a7bc144459/bridgetown-website/src/_docs/resources.md?plain=1#L248-L255

[jclusso]

The second part of this can be ignored once #793 is merged.

[jaredcwhite]

@jclusso Thanks for calling this out. Part of the issue I think is I really dislike that hooks API, as it's a holdover from Jekyll days, and I've been trying to move away from it in various ways. I'm realizing now there's not adequate documentation on how to use hook in initializer files, which is the new preferred way to define hooks going forward outside of a Builder. It needs updating here: https://www.bridgetownrb.com/docs/configuration/initializers