…alloc

… r=workingjubilee

Implement ptr_as_ref_unchecked

Implementation of rust-lang#122034.

Prefixed the feature name with `ptr_` for clarity.

Linked const-unstability to rust-lang#91822, so the post there should probably be updated to mentions the 3 new methods when/if this PR is merged.

Fix cannot usage in time.rs

Fix a small grammar error in usage of cannot in time.rs errors

… r=workingjubilee

default_alloc_error_hook: explain difference to default __rdl_oom in alloc

Though I'm not sure if that is really the reason that this code is duplicated. On no_std it may already be possible to call user-defined code on allocation failure.

…ion, r=fmease

Add raw identifier in a typo suggestion

Fixes rust-lang#68962

…workingjubilee

Describe and use CStr literals in CStr and CString docs

Mention CStr literals in the description of both types, and use them in some of the code samples for CStr. This is intended to make C string literals more discoverable.

Additionally, I don't think the orange "This example is not tested" warnings are very encouraging, so I have made the examples on `CStr` build.