doc(servant-foreign): reorder imports

The imports were ordered in the worst possible way, with all
undocumented small type definitions coming first and the actual meat
of the module coming at the very end, mixed in with irrelevant
functions.

This inverses that toxic ordering, showing the main function
first (`listFromAPI`) and then the main data type (`Req`) and the main
class (`HasForeignType`).

servant-foreign/src/Servant/Foreign.hs

@@ -3,20 +3,28 @@
 --
 -- See documentation of 'HasForeignType' for a simple example. 'listFromAPI' returns a list of all your endpoints and their foreign types, given a mapping from Haskell types to foreign types (conventionally called `ftypes` below).
 module Servant.Foreign
-  ( ArgType(..)
+  ( listFromAPI
+  , Req(..)
+  , defReq
+  , HasForeignType(..)
+  , GenerateList(..)
+  , HasForeign(..)
+  , NoTypes
+  , ArgType(..)
   , HeaderArg(..)
   , QueryArg(..)
-  , Req(..)
   , ReqBodyContentType(..)
   , Segment(..)
+  , isCapture
+  , captureArg
   , SegmentType(..)
   , Url(..)
-    -- aliases
+    -- * aliases
   , Path
   , Arg(..)
   , FunctionName(..)
   , PathSegment(..)
-    -- lenses
+    -- * lenses
   , argName
   , argType
   , argPath
@@ -32,7 +40,7 @@ module Servant.Foreign
   , queryArgName
   , queryArgType
   , headerArg
-    -- prisms
+    -- * prisms
   , _PathSegment
   , _HeaderArg
   , _ReplaceHeaderArg
@@ -41,16 +49,7 @@ module Servant.Foreign
   , _Normal
   , _Flag
   , _List
-    -- rest of it
+    -- * re-exports
-  , HasForeign(..)
-  , HasForeignType(..)
-  , GenerateList(..)
-  , NoTypes
-  , captureArg
-  , isCapture
-  , defReq
-  , listFromAPI
-    -- re-exports
   , module Servant.API
   , module Servant.Foreign.Inflections
   ) where