docs: comments for BlevmAggOutput and PublicWitness (#118)

Comments captured during a sync.

ibc/lightclients/groth16/witness.go

@@ -7,6 +7,7 @@ import (
 	"github.com/consensys/gnark/backend/witness"
 )
 
+// PublicWitness should match the public outputs of the SP1 program.
 type PublicWitness struct {
 	TrustedHeight             int64  // Provided by the relayer/user
 	TrustedCelestiaHeaderHash []byte // Provided by the ZK IBC Client

provers/blevm/common/src/lib.rs

@@ -14,9 +14,20 @@ pub struct BlevmOutput {
 
 #[derive(Serialize, Deserialize)]
 pub struct BlevmAggOutput {
+    // newest_header_hash is the last block's hash on the EVM roll-up.
+    // TODO: this may be removable.
     pub newest_header_hash: [u8; 32],
+    // oldest_header_hash is the earliest block's hash on the EVM roll-up.
+    // TODO: this may be removable.
     pub oldest_header_hash: [u8; 32],
-    pub celestia_header_hashes: Vec<[u8; 32]>,
+    // celestia_header_hashes is the range of Celestia blocks that include all
+    // of the blob data the EVM roll-up has posted from oldest_header_hash to
+    // newest_header_hash.
+    pub celestia_header_hashes: Vec<[u8; 32]>, // provided by Celestia state machine (eventually x/header)
+    // newest_state_root is the computed state root of the EVM roll-up after
+    // processing blocks from oldest_header_hash to newest_header_hash.
     pub newest_state_root: [u8; 32],
+    // newest_height is the most recent block number of the EVM roll-up.
+    // TODO: this may be removable.
     pub newest_height: u64,
 }