Turn lua into luau

Co-authored-by: ariel <aweiss@hey.com>

docs/metatable-type-functions.md

@@ -58,7 +58,7 @@ type ReversedIdentity = getmetatable<Identity>
 
 Due to `__metamethod`, additional behavior needs to be met. In the following code example, `MetatableType` should evaluate to `"No metatable here!"`:
 
-```lua
+```luau
 type metatable = {
 	__metatable: "No metatable here!"
 }