changelog: moving unreleased changes to the main section (#9769)

**What this PR does / why we need it**:
noticed that a couple of unreleased changes are incorrectly showing
under 2.8.0 release, moving them to the right place.
also adds the missing changelog entry for #7447

**Checklist**
- [X] Reviewed the
[`CONTRIBUTING.md`](https://github.com/grafana/loki/blob/main/CONTRIBUTING.md)
guide (**required**)
- [ ] Documentation added
- [ ] Tests updated
- [ ] `CHANGELOG.md` updated
- [ ] If the change is worth mentioning in the release notes, add
`add-to-release-notes` label
- [ ] Changes that require user attention or interaction to upgrade are
documented in `docs/sources/upgrading/_index.md`
- [ ] For Helm chart changes bump the Helm chart version in
`production/helm/loki/Chart.yaml` and update
`production/helm/loki/CHANGELOG.md` and
`production/helm/loki/README.md`. [Example
PR](d10549e3ec)

Signed-off-by: Ashwanth Goli <iamashwanth@gmail.com>

CHANGELOG.md

@@ -40,6 +40,9 @@
 * [9604](https://github.com/grafana/loki/pull/9604) **dannykopping**: Querier: configurable writeback queue bytes size
 * [9672](https://github.com/grafana/loki/pull/9672) **zeitlinger**: Add `alignLeft` and `alignRight` line formatting functions.
 * [9693](https://github.com/grafana/loki/pull/9693) **salvacorts** Add `keep` stage to LogQL.
+* [7447](https://github.com/grafana/loki/pull/7447) **ashwanthgoli** compactor: multi-store support.
+* [7754](https://github.com/grafana/loki/pull/7754) **ashwanthgoli** index-shipper: add support for multiple stores.
+* [8662](https://github.com/grafana/loki/pull/8662) **liguozhong**: LogQL: Introduce `distinct`
 
 ##### Fixes
 
@@ -167,10 +170,8 @@
 * [8271](https://github.com/grafana/loki/pull/8271) **kavirajk**: logql: Support urlencode and urldecode template functions
 * [8259](https://github.com/grafana/loki/pull/8259) **mar4uk**: Extract push.proto from the logproto package to the separate module.
 * [7906](https://github.com/grafana/loki/pull/7906) **kavirajk**: Add API endpoint that formats LogQL expressions and support new `fmt` subcommand in `logcli` to format LogQL query.
-* [7754](https://github.com/grafana/loki/pull/7754) **ashwanthgoli** index-shipper: add support for multiple stores.
 * [6675](https://github.com/grafana/loki/pull/6675) **btaani**: Add logfmt expression parser for selective extraction of labels from logfmt formatted logs
 * [8474](https://github.com/grafana/loki/pull/8474) **farodin91**: Add support for short-lived S3 session tokens
-* [8662](https://github.com/grafana/loki/pull/8662) **liguozhong**: LogQL: Introduce `distinct`
 * [8774](https://github.com/grafana/loki/pull/8774) **slim-bean**: Add new logql template functions `bytes`, `duration`, `unixEpochMillis`, `unixEpochNanos`, `toDateInZone`, `b64Enc`, and `b64Dec`
 
 ##### Fixes