Clean up code

Author: MaggieKimani1

src/Microsoft.OpenApi.Readers/OpenApiYamlDocumentReader.cs

@@ -112,7 +112,7 @@ public async Task<ReadResult> ReadAsync(YamlDocument input)
             }
 
             // Validate the document
-            if (_settings.RuleSet != null && _settings.RuleSet.Rules.Count() > 0)
+            if (_settings.RuleSet != null && _settings.RuleSet.Rules.Any())
             {
                 var openApiErrors = document.Validate(_settings.RuleSet);
                 foreach (var item in openApiErrors.OfType<OpenApiValidatorError>())

src/Microsoft.OpenApi/Validations/ValidationRuleSet.cs

@@ -114,7 +114,7 @@ public IEnumerable<ValidationRule> Rules
         {
             get
             {
-                return _rules.Values.SelectMany(v => v).ToList();
+                return _rules.Values.SelectMany(v => v);
             }
         }