chore: Add rust.vim edition workaround
@@ -6,3 +6,5 @@ use_small_heuristics = "Max"
group_imports = "StdExternalCrate"
format_code_in_doc_comments = true
doc_comment_code_block_width = 80
+# Workaround for https://github.com/rust-lang/rust.vim/issues/464
+edition = "2021"
