[New article] Configuring a .NET project for Git

[MackinnonBuck]

Describe the issue or suggestion

There's no documentation for the dotnet new gitignore command or other setup related to configuring .NET projects for Git integration.

It looks like this was originally addressed in #18262, but dotnet new <TEMPLATE> page has since removed any mention of dotnet new gitignore.

At a minimum, we could add a remark similar to what we have for global.json on that docs page.

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Associated WorkItem - 538907

[meaghanlewis]

@MackinnonBuck I'm going to add details about dotnet new gitignore to: https://learn.microsoft.com/en-us/dotnet/core/tools/dotnet-new-sdk-templates#preinstalled-templates