docs: update naming limit for lxd app

docs/how-to/run-on-lxd.md

@@ -7,7 +7,15 @@ By default, juju machines on LXD are containers.
 To run this charm on LXD, add `virt-type=virtual-machine` to the constraints during deployment:
 
 ```shell
-juju deploy github-runner --constraints="cores=2 mem=16G virt-type=virtual-machine" --config token=<TOKEN> --config path=<OWNER/REPO>
+juju deploy github-runner --constraints="cores=2 mem=16G virt-type=virtual-machine" \
+--config token=<TOKEN> --config path=<OWNER/REPO>
 ```
 
-This constraint ensures the juju machine hosting the charm is a LXD virtual machine. See [Managing resource usage](https://charmhub.io/github-runner/docs/managing-resource-usage) for recommendation on `cores` and `mem` constraint.
+This constraint ensures the juju machine hosting the charm is a LXD virtual machine. See
+[Managing resource usage](https://charmhub.io/github-runner/docs/managing-resource-usage) for
+recommendation on `cores` and `mem` constraint.
+
+### Notes
+
+The name of the application must not be longer than 29 characters. This is due to the nature of LXD
+pathing that must not exceed 108 bytes. 79 characters are reserved for path naming convention.