Pin memchr to 2.5.0 in the library rather than rustc_ast
The latest versions of `memchr` experience LTO-related issues when
compiling for windows-gnu [1], so needs to be pinned. The issue is
present in the standard library.
`memchr` has been pinned in `rustc_ast`, but since the workspace was
recently split, this pin no longer has any effect on library crates.
Resolve this by adding `memchr` as an _unused_ dependency in `std`,
pinned to 2.5. Additionally, remove the pin in `rustc_ast` to allow
non-library crates to upgrade to the latest version.
Link: https://github.com/rust-lang/rust/issues/127890 [1]
diff --git a/Cargo.lock b/Cargo.lock
index e973d7f..47ad7ab 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2177,9 +2177,9 @@
[[package]]
name = "memchr"
-version = "2.5.0"
+version = "2.7.4"
source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2dffe52ecf27772e601905b7522cb4ef790d2cc203488bbd0e2fe85fcb74566d"
+checksum = "78ca9ab1a0babb1e7d5695e3530886289c18cf2f87ec19a575a0abdce112e3a3"
[[package]]
name = "memmap2"
