plugins/pay: use json_ prefix for json command handlers.

That makes them intuitive to find with TAGS or grep.

Suggested-by: @cdecker
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

plugins/pay.c

@@ -848,7 +848,7 @@ static struct pay_status *add_pay_status(struct pay_command *pc,
 	return ps;
 }
 
-static struct command_result *handle_pay(struct command *cmd,
+static struct command_result *json_pay(struct command *cmd,
 				       const char *buf,
 				       const jsmntok_t *params)
 {
@@ -1035,7 +1035,7 @@ static void add_attempt(char **ret,
 	tal_append_fmt(ret, "}");
 }
 
-static struct command_result *handle_paystatus(struct command *cmd,
+static struct command_result *json_paystatus(struct command *cmd,
 					     const char *buf,
 					     const jsmntok_t *params)
 {
@@ -1156,7 +1156,7 @@ static struct command_result *listsendpays_done(struct command *cmd,
 	return command_success(cmd, ret);
 }
 
-static struct command_result *handle_listpays(struct command *cmd,
+static struct command_result *json_listpays(struct command *cmd,
 					    const char *buf,
 					    const jsmntok_t *params)
 {
@@ -1196,17 +1196,17 @@ static const struct plugin_command commands[] = { {
 		"pay",
 		"Send payment specified by {bolt11} with {amount}",
 		"Try to send a payment, retrying {retry_for} seconds before giving up",
-		handle_pay
+		json_pay
 	}, {
 		"paystatus",
 		"Detail status of attempts to pay {bolt11}, or all",
 		"Covers both old payments and current ones.",
-		handle_paystatus
+		json_paystatus
 	}, {
 		"listpays",
 		"List result of payment {bolt11}, or all",
 		"Covers old payments (failed and succeeded) and current ones.",
-		handle_listpays
+		json_listpays
 	}
 };