bug#47660: Add link to the ticket when someone reply

[bo0od]

Hi There,

When someone reply to my ticket and receive the message through email 
there is no URL included to the ticket, Which mean if i forgot what i 
have wrote before then i need to go and see what was the conversation by 
using ticket title in gnu bug which not nice.

Please add URL of the ticket always to the bottom.

ThX!