format_doc_comments stabilized as format_code_in_doc_comments

See rust-lang/rustfmt#3535 for background

Signed-off-by: Christopher Maier <cmaier@chef.io>

.rustfmt.toml

@@ -2,6 +2,7 @@
 edition = "2018"
 fn_args_layout = "Tall"
 force_explicit_abi = true
+format_code_in_doc_comments = true
 hard_tabs = false
 max_width = 100
 merge_derives = false
@@ -27,7 +28,6 @@ empty_item_single_line = true
 enum_discrim_align_threshold = 50
 fn_single_line = true
 force_multiline_blocks = true
-format_doc_comments = true
 format_macro_bodies = true
 format_macro_matchers = true
 format_strings = true