Fold the plxcobol refinements into the 1.1 changelog entry

1.1 has not actually been released yet, so STRING-APPEND, the % operator, the
PERFORM VARYING integer-FOR lowering, and the plxcobol benchmarks belong in 1.1
rather than a separate unreleased section.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: plx

CHANGELOG.md

@@ -4,23 +4,6 @@ All notable changes to plx are recorded here. The format follows
 [Keep a Changelog](https://keepachangelog.com/), and plx uses the extension
 version in `plx.control` (currently `1.0`).
 
-## [Unreleased]
-
-### Added
-
-- plxcobol: `STRING-APPEND <expr> TO <var>`, which lowers to the `plx_strbuild`
-  string builder (the COBOL counterpart of the other dialects' append operators),
-  and `%` as the modulo operator in expressions.
-
-### Changed
-
-- plxcobol: a `PERFORM VARYING v FROM a BY 1 UNTIL v > b` (or `>= b`) counting
-  loop now lowers to a plpgsql integer `FOR` loop instead of a `WHILE` with a
-  manual step, which is faster; other `PERFORM VARYING` forms still use `WHILE`.
-- Benchmarks now cover plxcobol (`bench/BENCHMARKS.md`): it matches plpgsql on
-  arith, strbuild, iter, and call, and is about 1.3x on the branch workload
-  because `EVALUATE` lowers to `CASE`.
-
 ## [1.1] - 2026-07-14
 
 ### Added
@@ -37,7 +20,15 @@ version in `plx.control` (currently `1.0`).
   `GET`; `RAISE`, `DISPLAY`, `ASSERT`, `CALL`, `COMMIT`/`ROLLBACK`. Data names
   are mapped to plpgsql identifiers (lower-cased, hyphens to underscores).
   See [doc/plxcobol.md](doc/plxcobol.md).
+- plxcobol: `STRING-APPEND <expr> TO <var>`, which lowers to the `plx_strbuild`
+  string builder (the COBOL counterpart of the other dialects' append operators),
+  and `%` as the modulo operator in expressions.
 - Regression suite `plxcobol` added to `make installcheck`.
+- Benchmarks now cover plxcobol (`bench/BENCHMARKS.md`): it matches plpgsql on
+  arith, strbuild, iter, and call, and is about 1.3x on the branch workload
+  because `EVALUATE` lowers to `CASE`. A `PERFORM VARYING v FROM a BY 1 UNTIL
+  v > b` counting loop lowers to a plpgsql integer `FOR` loop (other `PERFORM
+  VARYING` forms use `WHILE`).
 
 ### Upgrading