Examples need high-level explanation/summary

[eerhardt]

The examples look well written, but there are a few things I would like to see:

1. There should be a high-level explanation of each one, what is it doing and why. There are 5 different examples here. The first 2 and the last 2 appear to be duplicates - I can't tell the difference between them by reading them. Even between the first 2, it is subtle what the difference is (the first one you can't save and load the model, the second you can). It would be great to explicitly call this out before each example.
2. The 3rd example is fairly complicated, but with no explanation of what is happening. What defines a super alien? What is the overall scenario being achieved? What are the attributes for? It takes quite a bit to try to figure all these things out from the code without a high-level summary of the scenario.

---

Document Details

⚠ Do not edit this section. It is required for docs.microsoft.com ➟ GitHub issue linking.

• ID: 2af85725-9d23-0cff-c8ca-f915a94663bd
• Version Independent ID: 8afa2992-aa5b-4bb1-7841-6dcf26151288
• Content: CustomMappingCatalog.CustomMapping(TransformsCatalog, Action<TSrc,TDst>, String, SchemaDefinition, SchemaDefinition) Method (Microsoft.ML)
• Content Source: dotnet/xml/Microsoft.ML/CustomMappingCatalog.xml
• Product: dotnet-ml-api
• GitHub Login: @sfilipi
• Microsoft Alias: johalex

[najeeb-kazmi]

Duplicate examples are caused by a bug on the docs generation side. No ETA on that at the moment.

We should still provide high level explanations for the examples.