Append client version info to graffiti (#7558)

* #7201


  


Co-Authored-By: Tan Chee Keong <tanck@sigmaprime.io>

Co-Authored-By: chonghe <44791194+chong-he@users.noreply.github.com>

Co-Authored-By: Jimmy Chen <jimmy@sigmaprime.io>

Co-Authored-By: Tan Chee Keong <tanck2005@gmail.com>

validator_client/src/cli.rs

@@ -150,6 +150,16 @@ pub struct ValidatorClient {
     )]
     pub graffiti: Option<String>,
 
+    #[clap(
+        long,
+        requires = "graffiti",
+        help = "When used, client version info will be prepended to user custom graffiti, with a space in between. \
+        This should only be used with a Lighthouse beacon node.",
+        display_order = 0,
+        help_heading = FLAG_HEADER
+    )]
+    pub graffiti_append: bool,
+
     #[clap(
         long,
         value_name = "GRAFFITI-FILE",