Rollup merge of #63529 - andersk:release-notes-kleene, r=Centril
Rollup merge of #63529 - andersk:release-notes-kleene, r=Centril

RELEASES.md: ? is one of three Kleene operators

The slash and quotes in ?/“Kleene” appeared to define “Kleene” as the name for the `?` operator, which is not the case. Rust has three Kleene operators `*`, `+`, `?`.

([Pointed out](https://www.reddit.com/r/rust/comments/cprt0z/rust_1370_prerelease_testing/ewr90y3/) by /u/Sharlinator on Reddit.)

aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust