docs: add doc for concatall chain extension

src/main/wacc/backend/asmGenerator.scala

@@ -30,6 +30,14 @@ object asmGenerator {
   extension [T](chain: Chain[T])
     def +(item: T): Chain[T] = chain.append(item)
 
+    /** Concatenates multiple `Chain[T]` instances into a single `Chain[T]`, appending them to the
+      * current `Chain`.
+      *
+      * @param chains
+      *   A variable number of `Chain[T]` instances to concatenate.
+      * @return
+      *   A new `Chain[T]` containing all elements from `chain` concatenated with `chains`.
+      */
     def concatAll(chains: Chain[T]*): Chain[T] =
       chains.foldLeft(chain)(_ ++ _)