Add an example how Connection Resiliency can work with a System TransactionScope

[wertzui]

The documentation states that Connection Resiliency does not work with transactions by default.
However an example for working with an existing System.TransactionScope or System.Transaction is missing.
Providing an external Transaction is an important scenario for distributed transactions across multiple databases / servers.

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Document Details

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• ID: 876c88d4-2972-d905-28d7-56f9e589f309
• Version Independent ID: 29002343-fa42-2f49-3362-53592039b26d
• Content: Connection Resiliency - EF Core
• Content Source: entity-framework/core/miscellaneous/connection-resiliency.md
• Product: entity-framework
• Technology: entity-framework-core
• GitHub Login: @AndriySvyryd
• Microsoft Alias: avickers