Coding systems documentation

[Richard M Stallman]

    address@hidden I think this paragraph is no longer correct.
    address@hidden
       Most coding systems specify a particular character code for
     conversion, but some of them leave the choice unspecified---to be chosen
     heuristically for each file, based on the data.
    address@hidden ignore

I think these still exist.  For example, there are `undecided' and friends.