Merge branch 'adding-doc-for-listing-feature-flags' into 'master'

Adding listing feature flags command to documentation

See merge request !90028

doc/development/feature_flags/index.md

@@ -226,6 +226,16 @@ Feature flags **must** be used in the MR that introduces them. Not doing so caus
 [broken master](https://about.gitlab.com/handbook/engineering/workflow/#broken-master) scenario due
 to the `rspec:feature-flags` job that only runs on the `master` branch.
 
+## List all the feature flags
+
+To [use ChatOps](../../ci/chatops/index.md) to output all the feature flags in an environment to Slack, you can use the `run feature list`
+command. For example:
+
+```shell
+/chatops run feature list --dev
+/chatops run feature list --staging
+```
+
 ## Delete a feature flag
 
 See [cleaning up feature flags](controls.md#cleaning-up) for more information about