The markdown linter on the DevForum supports Lua, however, this support is for vanilla Lua. Which means you have acces on lints for stuff like io and open. These are not in Roblox Lua
print(io) --why is this linting???
It also does not provide lints for Roblox keywords.
print(typeof(foo)) --but why is this not??
The feature request suggests adding lints for Roblox keywords and removing lints for vanilla features not in Roblox (cough io). Optionally through a new language definition called luau as to not break old posts.