Enable syntax highlighting again

Author: phil-opp

config.toml

@@ -7,17 +7,16 @@ description = "Operating System Development in Rust"
 # Whether to automatically compile all Sass files in the sass directory
 compile_sass = false
 
-# Whether to do syntax highlighting
-# Theme can be customised by setting the `highlight_theme` variable to a theme supported by Zola
-highlight_code = true
-
 # Whether to build a search index to be used later on by a JavaScript library
 build_search_index = false
 
 # Generate RSS feed
 generate_feed = true
 feed_filename = "rss.xml"
 
+[markdown]
+highlight_code = true
+
 [link_checker]
 skip_prefixes = [
     "https://crates.io/crates", # see https://github.com/rust-lang/crates.io/issues/788