AST: add SingletonMethod::getObject

ql/src/codeql_ruby/ast/Method.qll

@@ -46,6 +46,9 @@ class SingletonMethod extends Callable, BodyStatement, @singleton_method {
 
   final override string getAPrimaryQlClass() { result = "SingletonMethod" }
 
+  /** Gets the object of this singleton method. */
+  final Expr getObject() { result = range.getObject() }
+
   /** Gets the name of this method. */
   final string getName() { result = range.getName() }
 }

ql/src/codeql_ruby/ast/internal/Method.qll

@@ -41,6 +41,8 @@ module SingletonMethod {
       result = generated.getName().(Generated::Setter).getName().getValue() + "="
     }
 
+    final Generated::AstNode getObject() { result = generated.getObject() }
+
     final override Generated::AstNode getChild(int i) { result = generated.getChild(i) }
 
     final override string toString() { result = this.getName() }