[lld] ReleaseNotes: add lld/ELF notes (PR #124508)

[Fangrui Song via llvm-commits]

MaskRay wrote:

> Suggestions for addition: Assuming it has made the release, this is a potentially breaking change for some people.
> 
> * [[ELF] Error for executable .note.GNU-stack unless -z execstack or -r #124068](https://github.com/llvm/llvm-project/pull/124068) Error for executable .note.GNU-stack unless -z execstack or -r
> 
> Not strictly a breaking change, but worth highlighting.
> 
> * [LLD] Deprecate --lto-basic-block-sections=labels ([[LLD] Deprecate --lto-basic-block-sections=labels #110697](https://github.com/llvm/llvm-project/pull/110697)) This option is now replaced by `--lto-basic-block-address-map`.

Thanks for the suggestion! Added the two items.

https://github.com/llvm/llvm-project/pull/124508