Clarify that number of threads is set by packages
Clarify that number of threads is set by packages

This commit clarifies that on systemd the packages already set the number of
threads for the Elasticsearch process.

Relates #27840

gingerwizard/elasticsearch,scorpionvicky/elasticsearch,gfyoung/elasticsearch,gfyoung/elasticsearch,ThiagoGarciaAlves/elasticsearch,rajanm/elasticsearch,gfyoung/elasticsearch,gingerwizard/elasticsearch,wangtuo/elasticsearch,coding0011/elasticsearch,kalimatas/elasticsearch,scottsom/elasticsearch,gingerwizard/elasticsearch,nknize/elasticsearch,ThiagoGarciaAlves/elasticsearch,coding0011/elasticsearch,scorpionvicky/elasticsearch,HonzaKral/elasticsearch,robin13/elasticsearch,rajanm/elasticsearch,gfyoung/elasticsearch,nknize/elasticsearch,ThiagoGarciaAlves/elasticsearch,scottsom/elasticsearch,kalimatas/elasticsearch,GlenRSmith/elasticsearch,wangtuo/elasticsearch,kalimatas/elasticsearch,fred84/elasticsearch,HonzaKral/elasticsearch,nknize/elasticsearch,uschindler/elasticsearch,HonzaKral/elasticsearch,rajanm/elasticsearch,scorpionvicky/elasticsearch,nknize/elasticsearch,GlenRSmith/elasticsearch,s1monw/elasticsearch,qwerty4030/elasticsearch,s1monw/elasticsearch,fred84/elasticsearch,scorpionvicky/elasticsearch,uschindler/elasticsearch,uschindler/elasticsearch,uschindler/elasticsearch,HonzaKral/elasticsearch,wangtuo/elasticsearch,nknize/elasticsearch,uschindler/elasticsearch,scottsom/elasticsearch,scottsom/elasticsearch,coding0011/elasticsearch,gingerwizard/elasticsearch,GlenRSmith/elasticsearch,kalimatas/elasticsearch,fred84/elasticsearch,GlenRSmith/elasticsearch,robin13/elasticsearch,wangtuo/elasticsearch,gfyoung/elasticsearch,coding0011/elasticsearch,qwerty4030/elasticsearch,ThiagoGarciaAlves/elasticsearch,rajanm/elasticsearch,s1monw/elasticsearch,qwerty4030/elasticsearch,scorpionvicky/elasticsearch,qwerty4030/elasticsearch,s1monw/elasticsearch,fred84/elasticsearch,coding0011/elasticsearch,robin13/elasticsearch,ThiagoGarciaAlves/elasticsearch,robin13/elasticsearch,qwerty4030/elasticsearch,rajanm/elasticsearch,gingerwizard/elasticsearch,kalimatas/elasticsearch,GlenRSmith/elasticsearch,gingerwizard/elasticsearch,robin13/elasticsearch,s1monw/elasticsearch,wangtuo/elasticsearch,gingerwizard/elasticsearch,ThiagoGarciaAlves/elasticsearch,fred84/elasticsearch,rajanm/elasticsearch,scottsom/elasticsearch