Hooks are poorly documented

[cortho]

WHAT Needs to be Documented?

• Hook prerequisites (type filesystem in info.xml)
• Symfony events

Obviously there already were tickets but they had been closed without any additional documentation. See

• Hooks documentation is missing information about pre-requisites #393
• Document symfony events #311

WHERE Does This Need To Be Documented (Link)?

most probably at
https://doc.owncloud.com/server/next/developer_manual/app/fundamentals/hooks.html

WHY Should This Change Be Made?

Some hooks/requirements are not documented at all.

(Optional) What Type Of Content Change Is This?

• New Content Addition
• Old Content Deprecation
• Existing Content Simplification
• Bug Fix to Existing Content

(Optional) Which Manual Does This Relate To?

• Admin Manual
• Developer Manual
• User Manual
• Android
• iOS
• Branded Clients
• Desktop Client
• Other