Update and fix custom condition documentation

[benstigsen]

#6361

Description

After having tried to create a custom condition for my extension, I ran into several issues following the documentation.

There were minor errors such as true being written as strue. But there were also some major issues, like things being imported which weren't used, extending the wrong classes and in general unclear ways to do stuff.

I ran into an issue requiring many hours of debugging, reading documentation and trial-and-error, where the custom condition was extending the wrong class, leading to something like args.host being undefined, resulting in the entire extension never being permitted, never reaching the timeout.

It also wasn't being shown how to make use of match, even though a condition config type was created to allow for this.

Type of suggestion

• Typo/grammar fix
• Updated outdated content
• New content
• Updates related to a new version
• Other

Product & version (if relevant)

Umbraco 14

[sofietoft]

Thanks a bunch for remaking the PR @benstigsen ! 😄 👏

I've gone through it, in an attempt to make it flow a little better with the next between the code snippets.
Please consider my suggestions when you have a minute 🙌

[benstigsen]

@sofietoft sure thing! I've committed your suggested changes 😄

[sofietoft]

Thanks for considering the suggestions @benstigsen ! 💪

Looks like we're finally ready to get this published.
I'll merge the PR 🎉

[benstigsen]

🎉