Update Data/ByteString/Builder/Prim.hs

Co-authored-by: Simon Jakobi <simon.jakobi@gmail.com>

Data/ByteString/Builder/Prim.hs

@@ -115,7 +115,7 @@ renderString cs =
 The code should be mostly self-explanatory. The slightly awkward syntax is
 because the combinators are written such that the size-bound of the resulting
 'BoundedPrim' can be computed at compile time. We also explicitly inline the
-@fixed22 primitive, which encodes a fixed tuple of characters, to ensure that
+@fixed2@ primitive, which encodes a fixed tuple of characters, to ensure that
 the bound computation happens at compile time. When encoding the following list
 of 'String's, the optimized implementation of @renderString@ is two times
 faster.
@@ -737,4 +737,3 @@ encodeCharUtf8 f1 f2 f3 f4 c = case ord c of
                x4 = fromIntegral $ (x .&. 0x3F) + 0x80
            in f4 x1 x2 x3 x4
 
-