Fix typo in doc of workspace-cleaner wrapper
Fix typo in doc of workspace-cleaner wrapper

it caused that literalinclude macro didn't have effect

Change-Id: Idfc7a5b03e70c656954719e2b9b770064fb79518

OSSystems/jenkins-job-builder,onshape/jenkins-job-builder,twc-openstack/jenkins-job-builder,dataxu/jenkins-job-builder,dataxu/jenkins-job-builder,wsoula/jenkins-job-builder,wikimedia/integration-jenkins-job-builder,phinexus/jenkins-job-builder,onshape/jenkins-job-builder,wsoula/jenkins-job-builder,puppetlabs/jenkins-job-builder,tamac-io/jenkins-job-builder,twc-openstack/jenkins-job-builder,twc-openstack/jenkins-job-builder,phinexus/jenkins-job-builder,OSSystems/jenkins-job-builder,onshape/jenkins-job-builder,OSSystems/jenkins-job-builder,puppetlabs/jenkins-job-builder,rsig/jenkins-job-builder,lukas-bednar/jenkins-job-builder,wikimedia/integration-jenkins-job-builder,OSSystems/jenkins-job-builder,phinexus/jenkins-job-builder,dataxu/jenkins-job-builder,gforcada/jenkins-job-builder,gforcada/jenkins-job-builder,wsoula/jenkins-job-builder,rsig/jenkins-job-builder,gforcada/jenkins-job-builder,gforcada/jenkins-job-builder,puppetlabs/jenkins-job-builder,wikimedia/integration-jenkins-job-builder,joostvdg/jenkins-job-builder,twc-openstack/jenkins-job-builder,wikimedia/integration-jenkins-job-builder,lukas-bednar/jenkins-job-builder,lukas-bednar/jenkins-job-builder,puppetlabs/jenkins-job-builder,tamac-io/jenkins-job-builder,rsig/jenkins-job-builder,phinexus/jenkins-job-builder,tamac-io/jenkins-job-builder,lukas-bednar/jenkins-job-builder,tamac-io/jenkins-job-builder,onshape/jenkins-job-builder,dataxu/jenkins-job-builder,wsoula/jenkins-job-builder,rsig/jenkins-job-builder,joostvdg/jenkins-job-builder,wikimedia/integration-jenkins-job-builder,gforcada/jenkins-job-builder,phinexus/jenkins-job-builder,joostvdg/jenkins-job-builder,joostvdg/jenkins-job-builder