C#: Qldoc tweaks.

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

@@ -42,6 +42,7 @@ class ControlFlowElement extends ExprOrStmtParent, @control_flow_element {
 
   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 @@ private predicate nonNullDef(Ssa::ExplicitDefinition def) {
 }
 
 /**
- * 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)