doc:s: add documentation and complete the readme

Cargo.lock

@@ -89,6 +89,15 @@ dependencies = [
  "clap_derive",
 ]
 
+[[package]]
+name = "clap-markdown"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d2a2617956a06d4885b490697b5307ebb09fec10b088afc18c81762d848c2339"
+dependencies = [
+ "clap",
+]
+
 [[package]]
 name = "clap_builder"
 version = "4.5.37"
@@ -197,6 +206,7 @@ name = "feddy"
 version = "0.1.0"
 dependencies = [
  "clap",
+ "clap-markdown",
  "clap_complete",
  "env_logger",
  "log",