Restore legacy `(. ...)` uncurried syntax with deprecation warning (#8383)

* Restore legacy `(. ...)` uncurried syntax with deprecation warning

Accept the pre-v11 dotted uncurried syntax in function parameters,
arguments, and type parameters so projects depending on libraries
that still use it can parse again. Emit a `Warnings.Deprecated` on
every occurrence, pointing at the leading dot, similar to the
deprecation warnings rewatch emits for `bs-*` fields in rescript.json.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* Rewatch: surface uncurried-dot deprecation for external deps

Rewatch suppresses warnings from external dependencies (users can't
act on them), but the legacy `(. ...)` uncurried-syntax deprecation
is a signal consumers need to see so they can report breakage
upstream before the syntax is removed. Add a small allow-list in
the stderr capture path for both the AST-parse phase and the
compile phase that keeps warning blocks mentioning that specific
deprecation while still dropping everything else from external
packages.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* Fix ocamlformat of res_core.ml and add PR link to changelog

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* Rewatch: normalize CRLF before splitting warning blocks

The "\n\n\n" block separator used by retain_critical_external_warnings
assumes LF line endings. On Windows bsc emits CRLF, so the splitter
would find no boundary and return the entire stderr — effectively
disabling external-dep warning suppression for any package that
emits the uncurried-dot deprecation alongside other warnings.

Normalize CRLF → LF before splitting. Add a CRLF test that exercises
the Windows-shaped input.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

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Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Co-authored-by: Christoph Knittel <ck@cca.io>