Remove c and c++ from highlight_languages

Fix 404 when trying to fetch highlight/languages/{c,c++}.min.js

config.toml

@@ -141,7 +141,7 @@ enableGitInfo = true
   #   For more info on the highlighting options, see:
   #   https://sourcethemes.com/academic/post/writing-markdown-latex/#highlighting-options
   highlight = true
-  highlight_languages = ["c", "c++", "go", "python" ]
+  highlight_languages = [ "go", "python" ]
   # highlight_style = "github"
 
   # Enable native social sharing buttons?