Fixed Github IO to use .NET display name (#18623)

eng/scripts/Language-Settings.ps1

@@ -156,15 +156,15 @@ function Publish-dotnet-GithubIODocs ($DocLocation, $PublicArtifactLocation)
 function Get-dotnet-GithubIoDocIndex()
 {
   # Update the main.js and docfx.json language content
-  UpdateDocIndexFiles -appTitleLang ".NET"
+  UpdateDocIndexFiles -appTitleLang $LanguageDisplayName
   # Fetch out all package metadata from csv file.
   $metadata = Get-CSVMetadata -MetadataUri $MetadataUri
   # Get the artifacts name from blob storage
   $artifacts =  Get-BlobStorage-Artifacts -blobStorageUrl $BlobStorageUrl -blobDirectoryRegex "^dotnet/(.*)/$" -blobArtifactsReplacement '$1'
   # Build up the artifact to service name mapping for GithubIo toc.
   $tocContent = Get-TocMapping -metadata $metadata -artifacts $artifacts
   # Generate yml/md toc files and build site.
-  GenerateDocfxTocContent -tocContent $tocContent -lang "NET"
+  GenerateDocfxTocContent -tocContent $tocContent -lang $LanguageDisplayName
 }
 
 # details on CSV schema can be found here