Allow multiple FileDataSourceAttribute to be used

[xj-ms]

Simply removing this will allow plugins to support multiple different file extensions. WPA already has the support for it as WPA always processes FileDataSourceAttribute in an IEnumerable. Even in this repo we have tests for multiple extensions (TryGetFileExtensions_FileDataSources_ReturnsExtensions)

[Copilot]

Pull request overview

This PR enables the use of multiple FileDataSourceAttribute instances on a single processing source class, allowing plugins to support multiple file extensions. The change is minimal—flipping the AllowMultiple parameter from false to true—because the Windows Performance Analyzer (WPA) infrastructure already processes these attributes as an enumerable collection. The PR also includes test updates demonstrating the new capability, along with minor documentation improvements and dependency updates.

Key Changes:

• Modified FileDataSourceAttribute to allow multiple instances per class (AllowMultiple = true)
• Updated test class MultiDataSourceCds to demonstrate multiple file extensions using separate attribute instances
• Corrected documentation spelling and updated .NET version guidance

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/Microsoft.Performance.SDK/Processing/FileDataSourceAttribute.cs	Changed AttributeUsage to allow multiple FileDataSourceAttribute instances on a single class
src/Microsoft.Performance.SDK.Runtime.Tests/ProcessingSourceReferenceTests.cs	Updated test class to demonstrate multiple file extensions with two separate FileDataSource attributes; removed unused imports
src/SDK.sln	Auto-updated Visual Studio version metadata (VS 17→18)
samples/SimpleDataSource/SampleAddIn.csproj	Updated SDK package reference from version 1.0.14-rc1 to 1.4.7-preview2
samples/SimpleDataSource/README.md	Fixed typo in documentation path ("documentaiton" → "documentation")
documentation/Using-the-SDK/Creating-your-plugin.md	Updated .NET version guidance to reference .NET 8 and clarify WPA compatibility requirements

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