Plugin Documentation mentions two ways to run the plugin in pipeline.

step([$class: 'MSTestPublisher', testResultsFile:"**/*.trx", failOnError: true, keepLongStdio: true])

The above command works.

mstest testResultsFile:"**/*.trx", keepLongStdio: true

But the mstest command doesnot work even though I installed the mstest plugin via Manage Jenkins > Manage Plugins. I dont see mstest listed in the pipeline Syntax as well.