chore: update theme.toml to the latest format

theme.toml

@@ -5,21 +5,21 @@ name = "Stack"
 license = "GPL-3.0-only"
 licenselink = "https://github.com/CaiJimmy/hugo-theme-stack/blob/master/LICENSE"
 description = "Card-style Hugo theme designed for bloggers"
-homepage = "https://theme-stack.jimmycai.com"
-tags = [
-    "blog", 
-    "responsive", 
-    "clean", 
-    "light", 
-    "dark", 
-    "personal"
-]
+homepage = "https://github.com/CaiJimmy/hugo-theme-stack"
+demosite = "https://theme-stack.jimmycai.com"
+
+tags = ["blog", "responsive", "clean", "light", "dark", "personal"]
+
 features = [
     "disqus",
     "photoswipe",
     "opengraph",
-    "widgets"
+    "widgets",
+    "darkmode",
+    "table of contents",
+    "search",
 ]
+
 min_version = "0.78.0"
 
 [author]