rustfmt: Update settings for latest nightly

.rustfmt.toml

@@ -5,7 +5,7 @@ newline_style = "Auto"
 use_small_heuristics = "Default"
 indent_style = "Block"
 wrap_comments = false
-format_doc_comments = false
+format_code_in_doc_comments = false
 comment_width = 80
 normalize_comments = false
 normalize_doc_attributes = false
@@ -34,7 +34,7 @@ struct_field_align_threshold = 0
 enum_discrim_align_threshold = 0
 match_arm_blocks = true
 force_multiline_blocks = false
-fn_args_density = "Tall"
+fn_args_layout = "Tall"
 brace_style = "SameLineWhere"
 control_brace_style = "AlwaysSameLine"
 trailing_semicolon = true