Add note about negative epoch times (#61379)
Add note about negative epoch times (#61379)

This commit adds a reminder to date type documentation that negative
epoch times are not supported.

relates #40983
scorpionvicky/elasticsearch,nknize/elasticsearch,scorpionvicky/elasticsearch,GlenRSmith/elasticsearch,robin13/elasticsearch,nknize/elasticsearch,nknize/elasticsearch,nknize/elasticsearch,GlenRSmith/elasticsearch,robin13/elasticsearch,GlenRSmith/elasticsearch,nknize/elasticsearch,robin13/elasticsearch,GlenRSmith/elasticsearch,scorpionvicky/elasticsearch,robin13/elasticsearch,robin13/elasticsearch,scorpionvicky/elasticsearch,scorpionvicky/elasticsearch,GlenRSmith/elasticsearch