Edit wording of the doc comment for rustc_span::symbol::Symbol::can_be_raw
to match related methods.

Thanks to Vadim Petrochenkov who [told me what the fix was][z]!

[z]: https://rust-lang.zulipchat.com/#narrow/stream/182449-t-compiler.2Fhelp/topic/finding.20which.20macro.20rule.20to.20use/near/220240422

Use consistent punctuation and capitalization in the list
of things re-exported in the prelude.

Also adds a (possibly missing) word.

Add a period to first line of module docs to match other modules in std.

…, r=davidtwco

Change the message for `if_let_guard` feature gate

`if-let` guards are now implemented by rust-lang#79051 🎉
Thanks `@camelid` for pointing this out 🙂

…, r=RalfJung

Fix memory leak in test "mem::uninit_write_slice_cloned_no_drop"

This fixes rust-lang#80116. I replaced the `Rc` based method I was using with a type that panics when dropped.

docs: Edit rustc_span::symbol::Symbol method

Edit wording of the doc comment for [rustc_span::symbol::Symbol::can_be_raw](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_span/symbol/struct.Symbol.html#method.can_be_raw) to match related methods.

Don't allow `const` to begin a nonterminal

Fixes rust-lang#79908.

Thanks to Vadim Petrochenkov who [told me what the fix was][z]!

[z]: https://rust-lang.zulipchat.com/#narrow/stream/182449-t-compiler.2Fhelp/topic/finding.20which.20macro.20rule.20to.20use/near/220240422

r? `@petrochenkov`

Fix typo in rustc_typeck docs

… r=lcnr

Edit formatting in Rust Prelude docs

Use consistent punctuation and capitalization in the list of things re-exported in the prelude.

Also adds a (possibly missing) word.

Add missing punctuation to std::alloc docs

Add a period to first line of module docs to match other modules in std.