refine the method option describe of hlsenc doc

Signed-off-by: LiuQi <liuqi@gosun.com>
Reviewed-by: Moritz Barsnick <barsnick@gmx.net>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

doc/muxers.texi

@@ -508,6 +508,17 @@ Emit @code{#EXT-X-PLAYLIST-TYPE:EVENT} in the m3u8 header. Forces
 @item hls_playlist_type vod
 Emit @code{#EXT-X-PLAYLIST-TYPE:VOD} in the m3u8 header. Forces
 @option{hls_list_size} to 0; the playlist must not change.
+
+@item method
+Use the given HTTP method to create the hls files.
+@example
+ffmpeg -re -i in.ts -f hls -method PUT http://example.com/live/out.m3u8
+@end example
+This example will upload all the mpegts segment files to the HTTP
+server using the HTTP PUT method, and update the m3u8 files every
+@code{refresh} times using the same method.
+Note that the HTTP server must support the given method for uploading
+files.
 @end table
 
 @anchor{ico}