fix(developer): Document the change of the _route parameter

[nickvergessen]

☑️ Resolves

• Breaking change from https://github.com/nextcloud/server/pull/42801/files#diff-e9bf496c8b197d60a7640f88f6fc4b5ff13cd41657c4e14f225ede16797e721eR139-R145
• Created an issue in talk fix(recording): Fix duplicate share message when sharing a recording … spreed#11863
• I saw the method being used in multiple apps and just by luck all of them had a "single word namespace" (photos, profiler, ...) and all of them only checked for the app id or controller name. But I think it still makes sense to document this.

🖼️ Screenshots

[provokateurin]

Thanks for catching this, I totally forgot about documenting this.