Add missing section comments

hugo.toml

@@ -1,6 +1,10 @@
+# Media types
+
 [mediatypes."application/atom+xml"]
 suffixes = ["xml"]
 
+# Hugo
+
 [module.hugoversion]
 min = "0.141.0"
 extended = true
@@ -94,6 +98,8 @@ source = "paige/node_modules/katex/dist"
 target = "assets/js/paige/katex"
 includefiles = ["katex.min.js"]
 
+# Output formats
+
 [outputformats.atom]
 basename = "atom"
 isplaintext = true