message: fix namespace and output-folder
diff: @@ -5,15 +5,22 @@ These settings apply only when `--go` is specified on the command line.
  ```yaml $(go)
  go:
  license-header: MICROSOFT_APACHE_NO_VERSION
  + namespace: changeanalysis
  clear-output-folder: true
  ```
  +### Go multi-api
  +
  +```yaml $(go) && $(multiapi)
  +batch:
  + - tag: package-2020-04-01-preview
  +```
  +
  ### Tag: package-2020-04-01-preview and go
  These settings apply only when `--tag=package-2020-04-01-preview --go` is specified on the command line.
  Please also specify `--go-sdks-folder=<path to the root directory of your azure-sdk-for-go clone>`.
  ```yaml $(tag) == 'package-2020-04-01-preview' && $(go)
  -namespace: Microsoft.ChangeAnalysis
  -output-folder: $(go-sdks-folder)/changeanalysis/Generated
  +output-folder: $(go-sdk-folder)/services/preview/$(namespace)/mgmt/2020-04-01-preview/$(namespace)
  ```
  