Deleted a symbol that caused doc creation to fail

[mccain]

When running make doc, it fails with the following:

[...]
cabal haddock --all
Running Haddock for mylittlepony-0.1.0.0...
Preprocessing executable 'encorec' for mylittlepony-0.1.0.0...
Haddock coverage:
  50% (  1 /  2) in 'CodeGen.Typeclasses'
  50% (  3 /  6) in 'Identifiers'
   2% (  1 / 50) in 'Types'
   0% (  0 / 13) in 'AST.Meta'
   4% (  1 / 26) in 'AST.AST'
  14% (  1 /  7) in 'AST.PrettyPrinter'
  22% (  2 /  9) in 'AST.Util'
   0% (  0 /  2) in 'AST.Desugarer'
   0% (  0 /  2) in 'Optimizer.Optimizer'
   0% (  0 /  2) in 'CodeGen.Preprocessor'

src/back/CCode/Main.hs:75:64: parse error on input ‘-- | Ampersand’
make: *** [doc] Error 1

This pull request fixes this problem and allows to correctly build the documentation.

[supercooldave]

Thanks for this. So easy, when you know how.