[enh] add request several hashs

rfc/0006_ws2p_v2.md

@@ -518,10 +518,13 @@ WARNING : Exception with the RBF api feature : In a WS2P connection between two
 |:-----:|---------------------|----------------------|--------------------|
 | 0     | EMPTY_REQUEST       | -                    | -                  |
 | 1     | CURRENT_BLOCKSTAMP  | -                    | -                  |
-| 2     | SPECIFIC_BLOCK_HASH | block_id (u32)       | -                  |
+| 2     | BLOCKS_HASHS        | begin_block_id (u32) | blocks_count (u16) |
 | 3     | CHUNK               | begin_block_id (u32) | blocks_count (u16) |
 | 4     | WOT_POOL            | folders_count (u16)  | min_cert (u8)      |
 
+BLOCKS_HASHS := In case of fork, to quickly find the fork point, the node will request the hashes of the ForkWindowsSize of the local blockchains of the other nodes.
+It would be counterproductive to ask directly for the entire blocks, when you will only need them if you actually decide to stack the corresponding branch.
+
 WOT_POOL := For network performance reasons, a Duniter-Rust node never shares its entire wot pool at once. It randomly selects `folders_count` folders among those having received at least `min_cert` certifications. It's the requesting node that sets the values of `min_cert` and `folders_count` according to its connection rate, its configuration and the rate of new folders it has obtained in these previous requests.
 
 ### REQUESTS RESPONSES