[GHC] #8888: Document Coercible in user's guide

[GHC]

#8888: Document Coercible in user's guide
-------------------------------------+------------------------------------
        Reporter:  goldfire          |            Owner:
            Type:  bug               |           Status:  new
        Priority:  normal            |        Milestone:  7.8.1
       Component:  Documentation     |          Version:  7.8.1-rc2
      Resolution:                    |         Keywords:
Operating System:  Unknown/Multiple  |     Architecture:  Unknown/Multiple
 Type of failure:  None/Unknown      |       Difficulty:  Unknown
       Test Case:                    |       Blocked By:
        Blocking:                    |  Related Tickets:
-------------------------------------+------------------------------------

Comment (by Joachim Breitner <mail@…>):

 In [changeset:"fc7aaf57a33ab07b70628c75fcf134fdf4e701e5/ghc-prim"]:
 {{{
 #!CommitTicketReference repository="ghc-prim"
 revision="fc7aaf57a33ab07b70628c75fcf134fdf4e701e5"
 Refer to the coercible paper in Coercible' docs

 Implements parts of #8888.
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8888#comment:10>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler