Corrected an essentially wrong use of "cluster" to "node".

[wkasdorp]

This was my reference: https://docs.microsoft.com/en-us/azure/virtual-machines/windows/allocation-failure, thx to Rodrigo Gomes.

[PRmerger]

@wkasdorp : Thanks for your contribution to the Azure documentation! The author, @cynthn, has been notified to review your proposed change.

[cynthn]

#sign-off @wkasdorp thanks for the fix!