msggen: Switch signatures to string instead of bytes

cln-grpc/proto/node.proto

@@ -1285,7 +1285,7 @@ message DecodepayResponse {
 	bytes payee = 4;
 	optional Amount amount_msat = 5;
 	bytes payment_hash = 6;
-	bytes signature = 7;
+	string signature = 7;
 	optional string description = 8;
 	optional bytes description_hash = 9;
 	uint32 min_final_cltv_expiry = 10;

cln-rpc/src/model.rs

@@ -3655,7 +3655,7 @@ pub mod responses {
 	    #[serde(skip_serializing_if = "Option::is_none")]
 	    pub amount_msat: Option<Amount>,
 	    pub payment_hash: Sha256,
-	    pub signature: Vec<u8>,
+	    pub signature: String,
 	    #[serde(skip_serializing_if = "Option::is_none")]
 	    pub description: Option<String>,
 	    #[serde(skip_serializing_if = "Option::is_none")]

contrib/msggen/msggen/gen/grpc.py

@@ -16,7 +16,7 @@ typemap = {
     'number': 'double',
     'pubkey': 'bytes',
     'short_channel_id': 'string',
-    'signature': 'bytes',
+    'signature': 'string',
     'string': 'string',
     'txid': 'bytes',
     'u8': 'uint32',  # Yep, this is the smallest integer type in grpc...

contrib/msggen/msggen/gen/rust.py

@@ -25,7 +25,7 @@ typemap = {
     'number': 'f64',
     'pubkey': 'PublicKey',
     'short_channel_id': 'ShortChannelId',
-    'signature': 'Vec<u8>',
+    'signature': 'String',
     'string': 'String',
     'txid': 'String',
     'float': 'f32',