String comments for translators

[Andrew Price]

Hi,

I'm currently adding comments to the strings in gfs2-utils which will 
eventually appear in the translation template, e.g.

     /* Translators: We use rpmatch(3) to match the answers to y/n
        questions in the user's own language, so the [y/n] here must also be
        translated to match one of the letters in the pattern printed by
        `locale -k yesexpr` and one of the letters in the pattern printed by
        `locale -k noexpr` */
     printf( _("Are you sure you want to proceed? [y/n]"));

If possible I'd like to only add comments to just the ambiguous and 
hard-to-translate strings. The above example was fairly obviously in 
need of explanation (I think) but other strings are less obviously in 
need of comments.

Do you have any guidelines or advice to help me identify which strings 
will require comments before they can be translated?

Thanks,

Andy