Docs: Fix reference to legacy tribe section
Docs: Fix reference to legacy tribe section

Original commit: elastic/x-pack-elasticsearch@5261193fc1b025d746eacefd4e1dbd43fe18bbc5

HonzaKral/elasticsearch,coding0011/elasticsearch,GlenRSmith/elasticsearch,HonzaKral/elasticsearch,HonzaKral/elasticsearch,gfyoung/elasticsearch,gfyoung/elasticsearch,uschindler/elasticsearch,robin13/elasticsearch,nknize/elasticsearch,scorpionvicky/elasticsearch,gingerwizard/elasticsearch,uschindler/elasticsearch,scorpionvicky/elasticsearch,robin13/elasticsearch,uschindler/elasticsearch,uschindler/elasticsearch,gfyoung/elasticsearch,gfyoung/elasticsearch,GlenRSmith/elasticsearch,nknize/elasticsearch,coding0011/elasticsearch,gingerwizard/elasticsearch,coding0011/elasticsearch,gingerwizard/elasticsearch,robin13/elasticsearch,GlenRSmith/elasticsearch,nknize/elasticsearch,nknize/elasticsearch,GlenRSmith/elasticsearch,GlenRSmith/elasticsearch,scorpionvicky/elasticsearch,nknize/elasticsearch,gingerwizard/elasticsearch,scorpionvicky/elasticsearch,HonzaKral/elasticsearch,gingerwizard/elasticsearch,coding0011/elasticsearch,scorpionvicky/elasticsearch,uschindler/elasticsearch,robin13/elasticsearch,gfyoung/elasticsearch,robin13/elasticsearch,coding0011/elasticsearch,gingerwizard/elasticsearch,gingerwizard/elasticsearch