* fix: restore @ts-expect-error for CacheProvider type mismatch
PR #30140 removed these comments assuming they were stale now that
the repo is on TypeScript 5. The comments were about the compiler
version, but the actual incompatibility is between react-inlinesvg/provider's
CacheProvider (typed to return a bare ReactNode) and this repo's pinned
@types/react@18.0.26, which requires JSX components to return Element | null.
ReactNode includes undefined, so the JSX usage fails type-checking.
Verified yarn build completes successfully with this restored.
Fixes#30170
* docs: explain the actual @ts-expect-error compatibility condition
Per @coderabbitai review on #30171: the old wording ("remove when
upgrading typescript to v5") was itself stale/misleading, since the
incompatibility is with the pinned @types/react version, not the
TypeScript compiler version. Documents the real condition instead.
