feat: support sublists for first available formatter

Co-authored-by: Andreas Palm <andreaspalm98@gmail.com>

lua/mason-conform/auto_install.lua

@@ -7,9 +7,17 @@ local function auto_install()
     local formatters_to_install = {}
     for _, formatters in pairs(formatters_by_ft) do
         for _, formatter in pairs(formatters) do
+            -- Support case where the user has defined multiple formatters
+            -- for said filetype. E.g javascript = { { "prettierd", "prettier" } }
+            if type(formatter) == "table" then
+                for _, f in pairs(formatter) do
+                    formatters_to_install[f] = 1
+                end
+            else
                 formatters_to_install[formatter] = 1
             end
         end
+    end
 
     for conformFormatter, _ in pairs(formatters_to_install) do
         local package = mapping.conform_to_package[conformFormatter]