Docs: link to ShortByteString from ByteString module (#193)

Data/ByteString.hs

@@ -47,6 +47,21 @@ module Data.ByteString (
         ByteString,
         StrictByteString,
 
+        -- ** Heap fragmentation
+        -- | With GHC, the 'ByteString' representation uses /pinned memory/,
+        -- meaning it cannot be moved by GC. While this is ideal for use with
+        -- the foreign function interface and is usually efficient,
+        -- this representation may lead to issues with heap fragmentation
+        -- and wasted space if the program retains many small 'ByteString's
+        -- live in memory over long durations or (de)allocates at high rates.
+        --
+        -- While 'ByteString' is indispensable when working with large blobs of
+        -- data and especially when interfacing with native C libraries, be sure
+        -- to also check the 'Data.ByteString.Short.ShortByteString' type.
+        -- As a type backed by /unpinned/ memory, @ShortByteString@ is more
+        -- similar to @Text@ on the heap, completely avoids fragmentation issues,
+        -- and in many use-cases may better suit your bytestring-storage needs.
+
         -- * Introducing and eliminating 'ByteString's
         empty,
         singleton,

bytestring.cabal

@@ -30,7 +30,8 @@ Description:
     .
     There is also a 'ShortByteString' type which has a lower memory overhead
     and can be converted to or from a 'ByteString'. It is suitable for keeping
-    many short strings in memory.
+    many short strings in memory, especially long-term, without incurring any
+    possible heap fragmentation costs.
     .
     'ByteString's are not designed for Unicode. For Unicode strings you should
     use the 'Text' type from the @text@ package.