C#: Instantiate shared Guards and shared ControlFlowReachability and replace nullness

csharp/ql/lib/semmle/code/csharp/controlflow/ControlFlowElement.qll

@@ -40,8 +40,9 @@
    */
   Nodes::ElementNode getAControlFlowNode() { result.getAstNode() = this }
 
   ControlFlow::Node getControlFlowNode() { result.getAstNode() = this }
 
+  /** Gets the basic block in which this element occurs. */
   BasicBlock getBasicBlock() { result = this.getAControlFlowNode().getBasicBlock() }
 
   /**

csharp/ql/lib/semmle/code/csharp/controlflow/ControlFlowGraph.qll

@@ -251,6 +251,7 @@ module ControlFlow {
       }
     }
 
+    /** A control flow node indicating normal termination of a callable. */
     class NormalExitNode extends AnnotatedExitNode instanceof Impl::NormalExitNode { }
 
     /** A node for a callable exit point. */

csharp/ql/lib/semmle/code/csharp/dataflow/Nullness.qll

@@ -118,7 +118,7 @@
 }
 
 /**
- * Holds if the `node` is a dereference `d` of SSA definition `def`.
+ * Holds if `node` is a dereference `d` of SSA definition `def`.
  */
 private predicate dereferenceAt(ControlFlow::Node node, Ssa::Definition def, Dereference d) {
   d = def.getAReadAtNode(node)
@@ -277,7 +277,7 @@
 
 private module NullnessFlow = Cf::ControlFlowReachability::Flow<NullnessConfig>;
 
 predicate maybeNullDeref(Dereference d, Ssa::SourceVariable v, string msg, Element reason) {
   exists(
     Ssa::Definition origin, Ssa::Definition ssa, ControlFlow::Node src, ControlFlow::Node sink
   |

shared/controlflow/codeql/controlflow/Cfg.qll

@@ -1185,6 +1185,7 @@ module MakeWithSplitting<
 
   final class AnnotatedExitNode = AnnotatedExitNodeImpl;
 
+  /** A control flow node indicating normal termination of a callable. */
   final class NormalExitNode extends AnnotatedExitNodeImpl {
     NormalExitNode() { this = TAnnotatedExitNode(_, true) }
   }