FromSql method when used with stored procedure cannot be composed error

It would be useful if this breaking changes document included how to handle the breaking change when amending EF code for stored procedures that return a single entity.

The suggested fix is to change
```
context.Products.FromSqlRaw("[dbo].[Ten Most Expensive Products]").FirstOrDefault();
```

To

```
context.Products.FromSqlRaw("[dbo].[Ten Most Expensive Products]").AsEnumerable().FirstOrDefault();
```

However whilst this works with tables it does not work for stored procedures where a single item is returned and no information on how to handle this is provided. After some trial and error I found this worked:
```
(await _context.Products.FromSqlInterpolated($"EXEC GetProducts").ToListAsync()).FirstOrDefault();
```

The issue does not apply for a list of items where this works:
```
await _context.Products.FromSqlInterpolated($"EXEC GetProducts").ToListAsync();
```

Could the docs be updated for next time I need to remind myself how I did this?

---
#### Document Details

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* ID: e4d0e044-b0cb-21e2-19c1-2f137da671ac
* Version Independent ID: 1cbedd95-8640-1649-9967-d0ef71633534
* Content: [Breaking changes in EF Core 3.0 - EF Core](https://docs.microsoft.com/en-us/ef/core/what-is-new/ef-core-3.0/breaking-changes#fromsqlsproc)
* Content Source: [entity-framework/core/what-is-new/ef-core-3.0/breaking-changes.md](https://github.com/dotnet/EntityFramework.Docs/blob/master/entity-framework/core/what-is-new/ef-core-3.0/breaking-changes.md)
* Product: **entity-framework**
* Technology: **entity-framework-core**
* GitHub Login: @ajcvickers
* Microsoft Alias: **avickers**