The correct proto.hrc is this of course:
<prototype name="haskell" group="rare" description="Haskell">
<location link="jar:common.jar!rare/haskell.hrc"/>
<filename>/\.(hs)$/i</filename>
</prototype>
You can use the above entry if you wish to install Haskell support in
a existing Colorer plugin.
Put the attached file in:
eclipse_dir/plugins/net.sf.colorer_0.9.9/colorer/hrc/auto
And add the proto.hrc entry to:
eclipse_dir/plugins/net.sf.colorer_0.9.9/colorer/hrc/proto.hrc