clarify serve-stale documentation, and add a floor for max-stale-ttl
- added a 1-second floor to max-stale-ttl similar to stale-answer-ttl; if set to 0, it will be silently updated to 1. - fixed the ARM entry on max-stale-ttl, which incorrectly suggested that the default was 0 instead of 1 week. - clarified rndc serve-stale documentation.
Showing with 58 additions and 37 deletions