Document our documentation process/workflow/guidelines

[rolfbjarne]

Ref: #14372, step 6

Write up a doc about how to write documentation, similar to what this is for MAUI, but specifically for our use case: dotnet/maui@main/docs/CodeDocumentationGuidelines.md

• Style guide: https://github.com/dotnet/dotnet-api-docs/wiki
• Recommended XML tags: https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/xmldoc/recommended-tags

[rolfbjarne]

Incomplete workflow / notes to self:

1. Push new dlls + xmls to the apidrop repository (currently using the ios-test branch).
   • New monikers might be needed. TODO: figure out how to do this (will likely have to ask someone or create a ticket somewhere).
2. Run this pipeline: https://apidrop.visualstudio.com/Content%20CI/_build?definitionId=8026 (currently disabled, someone with permissions need to classify/assign it and re-enable it).
3. If that pipeline succeeds, it'll push to the https://github.com/dotnet/macios-api-docs repository (currently configured to use the all-test branch.
4. A new build will show up in OPS here after a little while: https://ops.microsoft.com/#/repos/85f784f4-01e7-ffb8-ed06-a012f7d649c0?tabName=builds, look for errors/warnings in the build report. If anything needs to be fixed, do that and start over at the first bullet point.
5. Figure out what's the next step (presumably merge the changes in the all-test branch in macios-api-docs into main, and then maybe from main to live?)