Add mention to Pause Auto-Follower API in Upgrade Clusters docs (#48764)
Add mention to Pause Auto-Follower API in Upgrade Clusters docs (#48764)

Relates #46665
uschindler/elasticsearch,nknize/elasticsearch,gingerwizard/elasticsearch,robin13/elasticsearch,robin13/elasticsearch,HonzaKral/elasticsearch,gingerwizard/elasticsearch,GlenRSmith/elasticsearch,gingerwizard/elasticsearch,HonzaKral/elasticsearch,nknize/elasticsearch,scorpionvicky/elasticsearch,nknize/elasticsearch,scorpionvicky/elasticsearch,GlenRSmith/elasticsearch,scorpionvicky/elasticsearch,nknize/elasticsearch,uschindler/elasticsearch,HonzaKral/elasticsearch,uschindler/elasticsearch,GlenRSmith/elasticsearch,GlenRSmith/elasticsearch,robin13/elasticsearch,robin13/elasticsearch,GlenRSmith/elasticsearch,robin13/elasticsearch,scorpionvicky/elasticsearch,gingerwizard/elasticsearch,uschindler/elasticsearch,HonzaKral/elasticsearch,gingerwizard/elasticsearch,gingerwizard/elasticsearch,scorpionvicky/elasticsearch,gingerwizard/elasticsearch,nknize/elasticsearch,uschindler/elasticsearch