haddock fixes

compiler/basicTypes/Module.lhs

@@ -303,7 +303,7 @@ packageIdString = unpackFS . packageIdFS
 -- normal in the packages database, and you can still have multiple
 -- versions of them installed.  However, for each invocation of GHC,
 -- only a single instance of each wired-in package will be recognised
--- (the desired one is selected via @-package@/@-hide-package@), and GHC
+-- (the desired one is selected via @-package@\/@-hide-package@), and GHC
 -- will use the unversioned 'PackageId' below when referring to it,
 -- including in .hi files and object file symbols.  Unselected
 -- versions of wired-in packages will be ignored, as will any other

compiler/main/PackageConfig.hs

@@ -50,7 +50,7 @@ defaultPackageConfig = emptyInstalledPackageInfo
 -- package sub-system.
 --
 -- This means that in theory you could have multiple base packages installed
--- (for example), and switch between them using @-package@/@-hide-package@.
+-- (for example), and switch between them using @-package@\/@-hide-package@.
 --
 -- A 'PackageId' is a string of the form @<pkg>-<version>@.