[Feature Request] Feed Provider Implementation documentation

### Guidelines - [x] I have searched the issue tracker for [open](https://github.com/NeoApplications/Neo-Launcher/issues) and [closed](https://github.com/NeoApplications/Neo-Launcher/issues?q=is%3Aissue+is%3Aclosed) issues that are similar to the feature request I want to file, without success. - [x] I'm on the latest version. - [x] I'm not using a test build (alpha/beta/release-candidate). - [x] This issue contains only one feature request. ### Problem Description I'm trying to source the required information for implementing apps as feature providers but I'm struggling to find anything beyond the occasional reference. I can't seem to find anything on the wider web, either. Is there any documentation on this aspect I'm missing? ### Proposed Solution Additional documentation for this feature ### Alternatives Considered Searching other launchers for matching information, searching apps with this functionality for information, wider researching on google. ### Relevant information - Device: - Android Version: - ROM: (AOSP, CalyxOS, MIUI, GOS...) - App's Version: