Hook support

[martynassateika]

Docs: https://www.codeigniter.com/user_guide/general/hooks.html

• Editor notification when hooks are disabled in the config.
• Validation of hook entry (is hook point valid? does class exist? does function exist? etc)
• Inspection: multiple calls to the same hook (offer to make array entries multi-dimensional)

[martynassateika]

For any function that is referenced in the hooks file, add a line marker next to the function's declaration for easy access back to the hook.