refactor+feat: allow subsystems to send only declared messages, generate graphviz (#5314)

Closes #3774
Closes #3826

polkadot/node/overseer/overseer-gen/Cargo.toml

@@ -4,6 +4,7 @@ version = "0.9.19"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2021"
 description = "Generate an overseer including builder pattern and message wrapper from a single struct."
+autoexamples = false
 
 [dependencies]
 gum = { package = "tracing-gum", path = "../../gum" }
@@ -22,6 +23,16 @@ pin-project = "1.0"
 trybuild = "1.0.61"
 rustversion = "1.0.6"
 
+
+
+[[example]]
+name = "duo"
+crate-type = ["bin"]
+
+[[example]]
+name = "solo"
+crate-type = ["bin"]
+
 [features]
 default = []
 expand = ["polkadot-overseer-gen-proc-macro/expand"]