Python: fix definition of LocalSourceNode

and typo

python/ql/lib/semmle/python/dataflow/new/internal/FlowSummaryImplSpecific.qll

@@ -91,7 +91,7 @@ ReturnKind getReturnValueKind() { any() }
 
 /**
  * All definitions in this module are required by the shared implementation
- * (for source/sink interpretation), but they are unused for Ruby, where
+ * (for source/sink interpretation), but they are unused for Python, where
  * we rely on API graphs instead.
  */
 private module UnusedSourceSinkInterpretation {

python/ql/lib/semmle/python/dataflow/new/internal/LocalSources.qll

@@ -36,7 +36,7 @@ class LocalSourceNode extends Node {
   LocalSourceNode() {
     Stages::DataFlow::ref() and
     this instanceof ExprNode and
-    not simpleLocalFlowStep(_, this)
+    not simpleLocalFlowStepForTypetracking(_, this)
     or
     // We include all module variable nodes, as these act as stepping stones between writes and
     // reads of global variables. Without them, type tracking based on `LocalSourceNode`s would be