[HTML] Cleanup templates slightly

DiscordChatExporter.Core/Exporting/Writers/Html/MessageGroupTemplate.cshtml

@@ -1,8 +1,9 @@
 @using System
 @using System.Linq
 @using System.Threading.Tasks
+
 @namespace DiscordChatExporter.Core.Exporting.Writers.Html
-@inherits MiniRazor.TemplateBase<DiscordChatExporter.Core.Exporting.Writers.Html.MessageGroupTemplateContext>
+@inherits MiniRazor.TemplateBase<MessageGroupTemplateContext>
 
 @{
     string FormatDate(DateTimeOffset date) => Model.ExportContext.FormatDate(date);

DiscordChatExporter.Core/Exporting/Writers/Html/PostambleTemplate.cshtml

@@ -1,5 +1,5 @@
 @namespace DiscordChatExporter.Core.Exporting.Writers.Html
-@inherits MiniRazor.TemplateBase<DiscordChatExporter.Core.Exporting.Writers.Html.PostambleTemplateContext>
+@inherits MiniRazor.TemplateBase<PostambleTemplateContext>
 
 </div>
 

DiscordChatExporter.Core/Exporting/Writers/Html/PreambleTemplate.cshtml

@@ -1,7 +1,8 @@
 @using System
 @using System.Threading.Tasks
+
 @namespace DiscordChatExporter.Core.Exporting.Writers.Html
-@inherits MiniRazor.TemplateBase<DiscordChatExporter.Core.Exporting.Writers.Html.PreambleTemplateContext>
+@inherits MiniRazor.TemplateBase<PreambleTemplateContext>
 
 @{
     string FormatDate(DateTimeOffset date) => Model.ExportContext.FormatDate(date);

DiscordChatExporter.Core/Exporting/Writers/Html/StylesheetTemplate.cshtml

@@ -1,11 +1,13 @@
 @using System
+
 @namespace DiscordChatExporter.Core.Exporting.Writers.Html
-@inherits MiniRazor.TemplateBase<DiscordChatExporter.Core.Exporting.Writers.Html.PreambleTemplateContext>
+@inherits MiniRazor.TemplateBase<PreambleTemplateContext>
 
 @{
-    var isDarkTheme = string.Equals(Model.ThemeName, "Dark", StringComparison.OrdinalIgnoreCase);
-
-    string Themed(string darkVariant, string lightVariant) => isDarkTheme ? darkVariant : lightVariant;
+    string Themed(string darkVariant, string lightVariant) =>
+        string.Equals(Model.ThemeName, "Dark", StringComparison.OrdinalIgnoreCase)
+            ? darkVariant
+            : lightVariant;
 }
 
 <style>