Improve inflate() documentation on the use of Z_FINISH.

zlib.h

@@ -452,14 +452,17 @@ ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
   error.  However if all decompression is to be performed in a single step (a
   single call of inflate), the parameter flush should be set to Z_FINISH.  In
   this case all pending input is processed and all pending output is flushed;
-  avail_out must be large enough to hold all the uncompressed data.  (The size
-  of the uncompressed data may have been saved by the compressor for this
-  purpose.) The next operation on this stream must be inflateEnd to deallocate
-  the decompression state.  The use of Z_FINISH is not required to perform an
-  inflation in one step.  However it may be used to inform inflate that a
-  faster approach can be used for the single inflate() call.  Z_FINISH also
-  informs inflate to not maintain a sliding window if the stream completes,
-  which reduces inflate's memory footprint.
+  avail_out must be large enough to hold all of the uncompressed data for the
+  operation to complete.  (The size of the uncompressed data may have been
+  saved by the compressor for this purpose.) The use of Z_FINISH is not
+  required to perform an inflation in one step.  However it may be used to
+  inform inflate that a faster approach can be used for the single inflate()
+  call.  Z_FINISH also informs inflate to not maintain a sliding window if the
+  stream completes, which reduces inflate's memory footprint.  If the stream
+  does not complete, either because not all of the stream is provided or not
+  enough output space is provided, then a sliding window will be allocated and
+  inflate() can be called again to continue the operation as if Z_NO_FLUSH had
+  been used.
 
      In this implementation, inflate() always flushes as much output as
   possible to the output buffer, and always uses the faster approach on the