docs(changelog): use PR# 1851 for split entry

Author: pinin4fjords

CHANGELOG.md

@@ -9,11 +9,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Enhancements and fixes
 
-- [#1721](https://github.com/nf-core/rnaseq/issues/1721) - Split `PREPARE_GENOME` into `PREPARE_GENOME_REFERENCES` (FASTA / GTF / BED / transcript FASTA / chrom.sizes / rRNA / Kraken DB) and `PREPARE_GENOME_INDICES` (per-aligner index build/load) for clearer ownership; no user-facing parameter, output, or behaviour change.
 - [PR #1844](https://github.com/nf-core/rnaseq/pull/1844) - Bump version to 3.27.0dev after release 3.26.0; flip the MultiQC report links and RO-Crate URL/version back to dev
 - [PR #1848](https://github.com/nf-core/rnaseq/pull/1848) - Align `actions/checkout` SHA in `nf-test-arm.yml` and `nf-test-gpu.yml` with the template-derived `nf-test.yml` (`v6`) ([#1847](https://github.com/nf-core/rnaseq/issues/1847))
 - [PR #1849](https://github.com/nf-core/rnaseq/pull/1849) - Tidy-up batch addressing [#1845](https://github.com/nf-core/rnaseq/issues/1845): README/schema clarifications, `&` → `&&` in three guards, deduplicated `withName` blocks, and removal of the unmaintained `bin/fastq_dir_to_samplesheet.py` (use [nf-core/fetchngs](https://nf-co.re/fetchngs) for samplesheet generation)
 - [PR #1850](https://github.com/nf-core/rnaseq/pull/1850) - Use the active aligner's display name in the MultiQC `fail_mapped` per-sample status row, and drop the hardcoded "STAR" reference from the pipeline-completion `min_mapped_reads` warning, so Bowtie2 reports no longer mislabel the metric as STAR ([#1846](https://github.com/nf-core/rnaseq/issues/1846))
+- [PR #1851](https://github.com/nf-core/rnaseq/pull/1851) - Split `PREPARE_GENOME` into `PREPARE_GENOME_REFERENCES` (FASTA / GTF / BED / transcript FASTA / chrom.sizes / rRNA / Kraken DB) and `PREPARE_GENOME_INDICES` (per-aligner index build/load) for clearer ownership; no user-facing parameter, output, or behaviour change ([#1721](https://github.com/nf-core/rnaseq/issues/1721)).
 
 ## [[3.26.0](https://github.com/nf-core/rnaseq/releases/tag/3.26.0)] - 2026-05-07