fix comment in ps

Author: fengzhou-msft

eng/DownloadSharedSource.ps1

@@ -19,7 +19,7 @@ $files = @('AsyncLockWithValue.cs', 'ClientDiagnostics.cs', 'DiagnosticScope.cs'
     'Multipart/MultipartContent.cs', 'AzureKeyCredentialPolicy.cs', 'AppContextSwitchHelper.cs',
     'ConstantDelayStrategy.cs', 'DelayStrategy.cs', 'ExponentialDelayStrategy.cs', 'OperationPoller.cs', 'RetryAfterDelayStrategy.cs',
     'ForwardsClientCallsAttribute.cs', 'AsyncLockWithValue.cs', 'VoidValue.cs')
-// TODO: temporary change to target at support_lro_rehydration branch
+# TODO: temporary change to target at support_lro_rehydration branch
 $baseUrl = 'https://raw.githubusercontent.com/Azure/azure-sdk-for-net/support_lro_rehydration/sdk/core/Azure.Core/src/Shared/'
 DownloadAll $files $baseUrl $downloadPath