import/bob.cargo: Document Cargo and Cargo.build

Author: obiwac

import/bob/cargo.fl

@@ -1,6 +1,9 @@
 # SPDX-License-Identifier: MIT
 # Copyright (c) 2024 Aymeric Wibo
 
+# This class provides a way to build projects with Cargo.
 class Cargo {
+	# Build the Cargo project in the current directory.
+	# This expects a `Cargo.toml` file to be present and will return the path to the Cargo-generated artifact directory.
 	static proto build -> str
 }