Automatic merge from submit-queue
Rollout dry run
**What this PR does / why we need it**: rollout undo add dry-run implementation
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes#28219
**Release note**:
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```
rollout undo add dry-run option
```
The one side effect is that for the "kubectl help" commands a newline
is prepended to output, which will alter the yaml output.
Here we use dedent to format the code to match the output.
hack/update-generated-docs.sh has been run and the affected files have
been added.
Note: for describe.go we added a period to the end of an output message.
reqs:
- the kubectl cmd must support the -f | --filename flag
- the kubectl cmd must support visiting a dir one level deep,
or using more than one resource
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