Improved Determinism of NewNode (#237)

* Embed schema into `NewNode` object classes
The idea behind this change is to provide the option of allowing frontend developers to catch invalid edge types early on instead of when the `DiffGraph` is atomically merged into the graph.

Downstream, during development, we could have a validation flag on `X2Cpg` that would enable checks on `Ast` to validate neighbours as they are being set.

* Made the new functions part of the `NewNode` interface and resulting implementations

* Reverted Scala 3 imports

* Fixed Scala 2 string interpolation by workaround

* Including base types in valid neighbour calculations

* Unpacking neighbor base types and using US spelling of neighbor

* Update codegen/src/main/scala/overflowdb/codegen/CodeGen.scala

Co-authored-by: Michael Pollmeier <[email protected]>

* Improved determinism of `NewNode` with Sorting

---------

Co-authored-by: Michael Pollmeier <[email protected]>

Author: DavidBakerEffendi

codegen/src/main/scala/overflowdb/codegen/CodeGen.scala

@@ -1841,7 +1841,7 @@ class CodeGen(schema: Schema) {
       }.mkString(lineSeparator)
 
       def neighborEdgeStr(es: Map[String, Set[String]]): String =
-        es.map { case (k, vs) => s"$k -> Set(${vs.mkString(", ")})" }.mkString(", ")
+        es.toSeq.sortBy(_._1).map { case (k, vs) => s"$k -> Set(${vs.toSeq.sorted.mkString(", ")})" }.mkString(", ")
 
       s"""object $classNameNewNode {
          |  def apply(): $classNameNewNode = new $classNameNewNode