Fixed the grammatical mistake in an _index.md file (grafana#11226)

**What this PR does / why we need it**:

In this PR, I fixed the grammatical mistake in an _index.md file.

**Which issue(s) this PR fixes**:
Fixes #<issue number>

**Special notes for your reviewer**:

**Checklist**
- [x] Reviewed the
[`CONTRIBUTING.md`](https://github.com/grafana/loki/blob/main/CONTRIBUTING.md)
guide (**required**)
- [x] 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/setup/upgrade/_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](grafana@d10549e)
- [ ] If the change is deprecating or removing a configuration option,
update the `deprecated-config.yaml` and `deleted-config.yaml` files
respectively in the `tools/deprecated-config-checker` directory.
[Example
PR](grafana@0d4416a)

Signed-off-by: Bilal Khan <[email protected]>
Co-authored-by: J Stickler <[email protected]>

docs/sources/alert/_index.md

@@ -155,7 +155,7 @@ At the time of writing, these are the compatible backends that support this:
 - [Grafana Mimir](/docs/mimir/latest/operators-guide/reference-http-api/#remote-write)
 - [Thanos (`Receiver`)](https://thanos.io/tip/components/receive.md/)
 
-Here is an example remote-write configuration for sending to a local Prometheus instance:
+Here is an example of a remote-write configuration for sending data to a local Prometheus instance:
 
 ```yaml
 ruler: