#24359 bumped our MSRV to 1.95.0. We can now use `Vec::push_mut`.

Use it in `ReplaceWith` to remove an infallible `unwrap` which compiler previously couldn't prove was infallible. Previously it emitted a panicking branch, now it doesn't.

This code is on a cold path, so perf impact is miniscule, but why not use the best API for the job?

[#24359](#24359) bumped our MSRV to 1.95.0.

Now *at last* we have a decent way to guide branch layout: [`std::hint::cold_path`](https://doc.rust-lang.org/stable/core/hint/fn.cold_path.html). 🍾

Add the `likely` and `unlikely` functions that Rust's docs suggest as simple ways to use this capability.

…rds (#24383)

Rust 1.95 stabilized if-let guards in match arms (MSRV bumped in #24359). This converts the three places which guard on `is_some()` and then re-extract the same value in the body — the guard now binds the value directly:

- `oxc_semantic` `binder.rs` — `export_decl.declaration.is_some()` guard followed by `.as_ref().unwrap()`.
- `oxc_transformer` `typescript/annotations.rs` — `decl.declaration.is_some()` guard followed by an `is_some_and` re-check.
- `oxc_react_compiler` `validate_preserved_manual_memoization.rs` — `state.manual_memo_state.is_some()` guard followed by `.as_mut().unwrap()`; the guard now binds `&mut` directly. The sibling `StoreLocal` arm used the same unwrap idiom in a body `if`, converted to a let chain for consistency.

I audited the other ~15 `is_some()` match guards in the workspace: they only test the value without extracting it in the body, so they stay as plain guards.

Verified: crate tests pass, semantic coverage suites and Babel transform conformance produce **zero snapshot diffs**, clippy clean for the changed files.

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Rust 1.95 stabilized [`Atomic*::update`](https://doc.rust-lang.org/std/sync/atomic/struct.AtomicUsize.html#method.update) (MSRV bumped in #24359), the infallible sibling of `fetch_update` for closures that always produce a new value.

Both `fetch_update` call sites (`oxc_allocator/src/tracking.rs` and `tasks/track_memory_allocations`) used an always-`Some` closure, so they gain nothing from the fallible API — switching to `update` drops the ignored `Result` (`let _ =`) and the "cannot be `Err`" comments. Same CAS-loop semantics; `saturating_add` behavior unchanged.

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Rust 1.95 stabilized [`<*const T>::as_ref_unchecked`](https://doc.rust-lang.org/std/primitive.pointer.html#method.as_ref_unchecked) (MSRV bumped in #24359). This replaces the `ptr.as_ref().unwrap_unchecked()` idiom at its 5 call sites:

- `oxc_parser` `lexer/source.rs` `read()`/`read2()` — the doc comment there explains the idiom exists because producing a `&u8` carries `nonnull`/`dereferenceable` LLVM metadata that a raw deref does not (7% lexer speedup). `as_ref_unchecked` is implemented as exactly that reference production (`&*self`), so codegen is unchanged — it just skips the `Option` detour. Comment updated to name the new method.
- `oxc_codegen` `lib.rs` — `</script` search loop.
- `oxc_ast_visit` `utf8_to_utf16/translation.rs` — chunk read.
- `oxc_ast` `generated/ast_kind.rs` `AstKind::ty` — changed via its generator in `tasks/ast_tools`, regenerated with `just ast`.

Verified: `cargo test` for the touched crates, and parser/semantic/codegen conformance (test262 / babel / typescript / misc) with **zero snapshot diffs**. CodSpeed should show this perf-neutral.

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Rust 1.95 stabilized [`Layout::repeat`](https://doc.rust-lang.org/std/alloc/struct.Layout.html#method.repeat) (MSRV bumped in #24359), which the `UnstableLayoutMethods` polyfill trait in `bumpalo_alloc.rs` was waiting on (per its TODO comment).

It turns out the whole trait is deletable rather than just replaceable:

- The only `.repeat()` call outside the trait itself (`vec2/raw_vec.rs`) is inside a commented-out block.
- The live `Layout::array::<T>(n)` calls already resolve to the inherent std method (stable since 1.44), not the trait method.
- `padding_needed_for` was only used by the trait's own `repeat` impl.

Also drops the two `#![allow(unstable_name_collisions)]` attributes, which only existed because the trait methods collided with the then-unstable std inherent methods.

Net: -59 lines, no behavior change. `cargo check/clippy/test -p oxc_allocator` all clean.

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