Fixed CanvasLayout markdown being picked up by template

[Arlodotexe]

This PR fixes an issue where tabs for CanvasLayout were showing when running the ProjectTemplate solution.

closes #116

[michael-hawker]

Following the steps in #116 (building template solution for UWP and then trying to run the WinAppSDK one after) and got this:

3>CSC : error CS0016: Could not write to output file 'H:\code\Labs-UWP\template\lab\samples\ProjectTemplate.WinAppSdk\obj\x64\Debug\net6.0-windows10.0.19041.0\generated\CommunityToolkit.Labs.Core.SourceGenerators\CommunityToolkit.Labs.Core.SourceGenerators.ToolkitSampleMetadataGenerator\ToolkitDocumentRegistry.g.cs' -- 'Could not find a part of the path 'H:\code\Labs-UWP\template\lab\samples\ProjectTemplate.WinAppSdk\obj\x64\Debug\net6.0-windows10.0.19041.0\generated\CommunityToolkit.Labs.Core.SourceGenerators\CommunityToolkit.Labs.Core.SourceGenerators.ToolkitSampleMetadataGenerator\ToolkitDocumentRegistry.g.cs'.'
3>CSC : error CS0016: Could not write to output file 'H:\code\Labs-UWP\template\lab\samples\ProjectTemplate.WinAppSdk\obj\x64\Debug\net6.0-windows10.0.19041.0\generated\CommunityToolkit.Labs.Core.SourceGenerators\CommunityToolkit.Labs.Core.SourceGenerators.ToolkitSampleMetadataGenerator\ToolkitSampleRegistry.g.cs' -- 'Could not find a part of the path 'H:\code\Labs-UWP\template\lab\samples\ProjectTemplate.WinAppSdk\obj\x64\Debug\net6.0-windows10.0.19041.0\generated\CommunityToolkit.Labs.Core.SourceGenerators\CommunityToolkit.Labs.Core.SourceGenerators.ToolkitSampleMetadataGenerator\ToolkitSampleRegistry.g.cs'.'

Doing a git clean and then building then resulted in these errors:

3>CSC : error CS0006: Metadata file 'H:\code\Labs-UWP\common\CommunityToolkit.Labs.Core.SourceGenerators\bin\Debug\netstandard2.0\CommunityToolkit.Labs.Core.SourceGenerators.dll' could not be found
3>CSC : error CS0006: Metadata file 'H:\code\Labs-UWP\common\CommunityToolkit.Labs.Core.SourceGenerators.XamlNamedPropertyRelay\bin\Debug\netstandard2.0\CommunityToolkit.Labs.Core.SourceGenerators.XamlNamedPropertyRelay.dll' could not be found
3>CSC : error CS0006: Metadata file 'H:\code\Labs-UWP\template\lab\samples\ProjectTemplate.Sample\bin\Debug\net6.0-windows10.0.19041.0\ProjectTemplate.Sample.dll' could not be found

Going to go to main and try there and see what happens. We'll also see what happens in the CI as it should be building all these... and the initial commit was fine.

[michael-hawker]

Not sure what's wrong with my setup. I hit the same issue in main. But then was able to build the all solution fine. It's working for Arlo in the CI. So let's move forward, and we'll see if anyone else hits an issue.