Add Inline docs about mason-lspconfig

[mattcargile]

I think it would be helpful to have some words about mason-lspconfig's involvement in the config. I added the below in my config.

  -- mason-lspconfig has methods to map the keys in the above servers table for `nvim-lspconfig`.
  -- There isn't a need to run `setup` unless there is a specific lsp that might have custom config.
  -- For instance, `powershell_es` has the `bundle_path` specified in `mason-lspconfig` making it
  -- easier to auto enable. It is more problematic because the below will enable the lsp too.

Maybe there could be a link to the docs with maybe the same excerpt like the below.

translate between nvim-lspconfig server names and mason.nvim package names (e.g. lua_ls <-> lua-language-server)