fix: the URL for language switching is incorrect

modules/docs/app/VoloDocs.Web/VoloDocsWebModule.cs

@@ -123,6 +123,7 @@ namespace VoloDocs.Web
             {
                 options.Languages.Add(new LanguageInfo("cs", "cs", "Čeština"));
                 options.Languages.Add(new LanguageInfo("en", "en", "English"));
+                options.Languages.Add(new LanguageInfo("pt-BR", "pt-BR", "Português"));
                 options.Languages.Add(new LanguageInfo("fi", "fi", "Finnish"));
                 options.Languages.Add(new LanguageInfo("fr", "fr", "Français"));
                 options.Languages.Add(new LanguageInfo("hi", "hi", "Hindi", "in"));

modules/docs/src/Volo.Docs.Web/Areas/Documents/TagHelpers/TreeTagHelper.cs

@@ -137,7 +137,7 @@ namespace Volo.Docs.Areas.Documents.TagHelpers
                     }
                     else if (node.LastSignificantUpdateTime != null && node.LastSignificantUpdateTime + TimeSpan.FromDays(14) > DateTime.Now)
                     {
-                        var updBadge = sb.Append("<span class='badge badge-light ml-2' title=\"").Append(_localizer["UpdatedExplanation"]).Append("\">").Append(_localizer["Upd"]).Append("</span>");
+                        var updBadge = sb.Append("<span class='badge badge-light ml-2' title=\"").Append(_localizer["UpdatedExplanation"]).Append("\">").Append(_localizer["Upd"]).Append("</span>").ToString();
                         badgeStringBuilder.Append(updBadge);
                     }
                 }

modules/docs/src/Volo.Docs.Web/Pages/Documents/Project/Index.cshtml.cs

@@ -212,7 +212,7 @@ namespace Volo.Docs.Pages.Documents.Project
             var sb = new StringBuilder();
 
             var returnUrl = sb.Append(DocumentsUrlPrefix).Append(LanguageCode).Append("/").Append(ProjectName)
-                .Append("/").Append(LatestVersionInfo.IsSelected ? DocsAppConsts.Latest : Version).Append("/").Append(DocumentName);
+                .Append("/").Append(LatestVersionInfo.IsSelected ? DocsAppConsts.Latest : Version).Append("/").Append(DocumentName).ToString();
 
             sb.Clear();
             
@@ -454,6 +454,8 @@ namespace Volo.Docs.Pages.Documents.Project
                         language.Code == LanguageCode
                         )
                     );
+
+                sb.Clear();
             }
         }