Docs: fix missing start of code comment in config example (CrunchyData#118)

This commit adds the missing comment markup and makes the comment match
similar configs in the code base, like e.g. README.md or
config/pg_tileserv.toml.example.

Author: tomka

hugo/content/installation/_index.md

@@ -136,6 +136,6 @@ DefaultMinZoom = 0
 DefaultMaxZoom = 22
 # Allow any page to consume these tiles
 CORSOrigins = *
-tra logging information?
+# Output extra logging information?
 Debug = false
 ```