C++: Add QLDoc. Also actually implement 'uninitializedNode' since there's no reason not to do so.

Author: MathiasVP

cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowNodes.qll

@@ -926,19 +926,25 @@ module Public {
   }
 
   /**
-   * DEPRECATED: See UninitializedNode.
-   *
    * Gets the `Node` corresponding to the value of an uninitialized local
    * variable `v`.
    */
-  Node uninitializedNode(LocalVariable v) { none() }
+  Node uninitializedNode(LocalVariable v) { result.asUninitialized() = v }
 
+  /**
+   * Holds if `indirectOperand` is the dataflow node that represents the
+   * indirection of `operand` with indirection index `indirectionIndex`.
+   */
   predicate hasOperandAndIndex(
     IndirectOperand indirectOperand, Operand operand, int indirectionIndex
   ) {
     indirectOperand.hasOperandAndIndirectionIndex(operand, indirectionIndex)
   }
 
+  /**
+   * Holds if `indirectInstr` is the dataflow node that represents the
+   * indirection of `instr` with indirection index `indirectionIndex`.
+   */
   predicate hasInstructionAndIndex(
     IndirectInstruction indirectInstr, Instruction instr, int indirectionIndex
   ) {