Tweak config.toml and .gitignore per Codex's suggestions

Signed-off-by: Danila Fedorin <danila.fedorin@gmail.com>

config.toml

@@ -1,7 +1,5 @@
 baseURL = "https://danilafe.com"
 theme = "vanilla"
-pygmentsCodeFences = true
-pygmentsUseClasses = true
 summaryLength = 20
 
 defaultContentLanguage = 'en'
@@ -22,6 +20,9 @@ defaultContentLanguage = 'en'
   home = ["html","rss","toml"]
 
 [markup]
+  [markup.highlight]
+    codeFences = true
+    noClasses = false
   [markup.tableOfContents]
     endLevel = 4
     ordered = false