[Ready] Make 'Monsters dangerously close', etc messages more specific

This addresses #9253.

`Monster dangerously close! Stop reading?` ->  `You see the zombie approaching! Stop reading?`
`You were hurt! Stop reading?` -> `You were attacked by the zombie! Stop reading?`
`Hostiles are nearby! Start butchering anyway?` -> `You see the zombie nearby! Start butchering anyway?`
`Monster spotted--safe mode is on!` -> `Spotted zombie--safe mode is on!`