Improve documentation

[kabiroberai]

• Fill in stub guides
• Add more examples
• Add basic documentation in template, similar to the regular tweak template
• Describe how to hook classes which can't be linked (@interface, Dynamic, etc.)
• Add troubleshooting guide (mention handleError, Theos troubleshooting, etc.)

Document QoL features:

• Automatic @available handling
• Calling other hooks' supr/orig methods

Document directives:

• disable
• new
• returns_retained
• supr_tramp
• Schemas

[kabiroberai]

It was; unfortunately I was pressed on time and didn't want to keep devs waiting when they'd already started making tweaks with Orion. This issue is, of course, still something I plan to get to, however I haven't been able to make much time for it yet due to other work. In the meanwhile, if you need any help with the features mentioned in the issue then feel free to get in touch on the Theos discord server.