Add this keyword to fix some warnings

Author: lulunac27a

text-counter-razor/Pages/Error.cshtml.cs

@@ -10,18 +10,18 @@ public class ErrorModel : PageModel
     {
         public string? RequestId { get; set; }
 
-        public bool ShowRequestId => !string.IsNullOrEmpty(RequestId);
+        public bool ShowRequestId => !string.IsNullOrEmpty(this.RequestId);
 
         private readonly ILogger<ErrorModel> _logger;
 
         public ErrorModel(ILogger<ErrorModel> logger)
         {
-            _logger = logger;
+            this._logger = logger;
         }
 
         public void OnGet()
         {
-            RequestId = Activity.Current?.Id ?? HttpContext.TraceIdentifier;
+            this.RequestId = Activity.Current?.Id ?? this.HttpContext.TraceIdentifier;
         }
     }
 }