This is a Bug Report

kubectl PowerShell example does not work in Windows. cat is an alias for Get-Content, which by default parses a file line-by-line.

Proposed Solution:
Change PowerShell example to use the -Raw flag in Get-Content cmdlet (and change cat to Get-Content to avoid ambiguity between the Windows Get-Command alias and Unix cat command).

kubectl patch deployment patch-demo --patch $(Get-Content patch-file.yaml -Raw)

Page to Update:
https://kubernetes.io/docs/tasks/run-application/update-api-object-kubectl-patch/