Combine the 0.88 RC sections into v0.88.0 (#59122)

Summary:
Pull Request resolved: #59122

Replaces the six per-RC headings (rc.0, rc.1, rc.2, rc.3, rc.4, rc.6) with the single `## v0.88.0` section the stable release publishes. 173 entries in, 170 out, deduped by commit sha, sorted alphabetically by scope, empty sections omitted.

Four entries removed and one added, each verified against `0.88-stable` by content rather than by sha ancestry:

- `11f9a7f4491` RCTArrayBuffer codegen change: reverted by 639cded. `RCTArrayBuffer` appears in 0 files on the branch.
- `ab2ea649e65` TurboModule EventEmitter payload alignment: reverted by 070af03, a clean inverse (497 lines each way).
- `4043e818f16` automatic `accessible` with `role`: reverted by adde1e5. `View.js` has no `role != null` guard on the branch. This revert is hand-written with no `This reverts commit` line, so it is not auto-detectable and was removed by hand.
- `47fad096a4f` `npx react-native spm`: the content shipped in 0.87. The v0.87.1 tag carries 42 spm files and the 0.87 release post announces Swift Package Manager. The main-branch commit landed after the 0.87 cut, so sha ancestry reports it as new; content says otherwise.
- `8415753e21c` iOS `fontVariationSettings`: ADDED. It is on `0.88-stable`, absent from v0.87.1 and so new in 0.88, but the generator never emitted it. Without this the changelog implies the feature is Android-only while the release post documents iOS support.

Every commit link was checked to resolve and to match its link text.

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landed-with-radar-review

Differential Revision: D125284660

fbshipit-source-id: 70164a628e1a6fb9c3e10ee02b0be67401d4e8bd

Author: fabriziocucci