fn_args_layout is now deprecated.
This option was renamed to better communicate that it affects the layout
of parameters in function signatures and not the layout of arguments in
function calls.
Because the `fn_args_layout` is a stable option the renamed option is
also stable, however users who set `fn_args_layout` will get a warning
message letting them know that the option has been renamed.
When either one of these two options are set to `true`, each should take
precedence over the brace_style option.
This commit does not introduce any formatting change to the default
configuration, so no version gate is required.
