Rollup merge of #137451 - compiler-errors:synm, r=Noratrieb

FIx `sym` -> `syn` typo in tail-expr-drop-order type opt-out

The #131326 PR attempts to reduce some false positives for the `tail_expr_drop_order` lint by hard-coding some common ecosystem crate names. Specifically, I believe it attempts to opt out the drop impls from `syn` which only exist as optimizations.

However, this was typo'd like "sym", which is a crate that has been [yanked](https://crates.io/crates/sym) (lol). This PR fixes that.

cc `@dingxiangfei2009` `@nikomatsakis` -- did I mistake this? Was this meant to be a different crate?

`@bors` rollup

Author: tgross35