improve the script error code and return documentation in hooks

hello,

we need to specify that if there is an error the script will exit in error and show it in the interface

Cheers

(from redmine: issue id 4808, created on 2016-05-26, closed on 2016-09-01)

• Relations:
  • relates #4793 (closed)
• Custom Fields:
  • Bug in version: 1.0.12
  • Support contract: Silver