Add JSX children note to TypeScript 5.8 release notes

[KirtiRamchandani]

Problem

TypeScript 5.8 changed how JSX children are checked under the automatic JSX runtimes, but the 5.8 release notes do not mention the behavior change. This leaves JSX library authors without an upgrade note when children needs to be declared explicitly in their props.

Root cause

The TypeScript change in microsoft/TypeScript#60880 made react-jsx and react-jsxdev type checking match the emitted runtime behavior: JSX children are passed through a children prop, and JSX.ElementChildrenAttribute is no longer used to choose a different prop name for those runtimes.

Solution

Add a short “Notable Behavioral Changes” entry to the TypeScript 5.8 release notes explaining the behavior and showing the shape JSX typings should include when elements accept children.

Tests

• git diff --check -- "packages/documentation/copy/en/release-notes/TypeScript 5.8.md"

Fixes microsoft/TypeScript#63212.