add some comments in derive

derive/src/compile_bytecode.rs

@@ -32,8 +32,11 @@ static CARGO_MANIFEST_DIR: Lazy<PathBuf> = Lazy::new(|| {
 });
 
 enum CompilationSourceKind {
+    /// Source is a File (Path)
     File(PathBuf),
+    /// Direct Raw sourcecode
     SourceCode(String),
+    /// Source is a directory
     Dir(PathBuf),
 }