Bracing options for modules

[TimBednarzyk]

There should be an option to configure the brace style for modules just like control_brace_style, fn_brace_style, and item_brace_style.

Currently, only the following is possible:

#[cfg(test)]
mod tests {
  #[test]
  fn it_works()
  {
  }
}

However, if there was a mod_brace_style then there could be an option for "AlwaysNextLine" which makes the above code look like the following:

#[cfg(test)]
mod tests
{
  #[test]
  fn it_works()
  {
  }
}

[nrc]

A module is just an item, so module bracing should be dictated by item_brace_style.

[TimBednarzyk]

This is the contents of the rustfmt.toml that resulted in the former block of code:

control_brace_style = "AlwaysNextLine"
fn_brace_style = "AlwaysNextLine"
item_brace_style = "AlwaysNextLine"
tab_spaces = 2