docs: fix link; update folder name for docs sidenav autogen (#964)

## Description

Due to the way that the sidenav autogenerates, the nested `Reference ->
Configuration -> Custom Resources` folder currently has a hyphen:

![Screenshot 2024-10-25 at 2 00
06 PM](https://github.com/user-attachments/assets/04dd1c8b-e75f-4fe5-bfbd-46969f72575e)

Using a space in the folder name resolves this issue (and does not
affect the link, which still uses a hyphen).

_Side note: there is open discussion on the Starlight repo on how to
improve the DX of this behavior._

Additionally, there was a broken link on the UDS User Groups page.

## Related Issue

N/A

## Type of change

- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [X] Other (security config, docs update, etc)

## Checklist before merging

- [X] Test, docs, adr added or updated as needed
- [ ] [Contributor
Guide](https://github.com/defenseunicorns/uds-template-capability/blob/main/CONTRIBUTING.md)
followed

Co-authored-by: Chance <[email protected]>

docs/reference/configuration/uds-user-groups.md

@@ -34,7 +34,7 @@ All groups are under the Uds Core parent group. Frequently a group will be refer
 
 ### Identity Providers ( IDP )
 
-UDS Core ships with a [templated](https://github.com/defenseunicorns/uds-identity-config/blob/main/src/realm.json#L1712-L1813) Google SAML IDP, more documentation to configure the `realmInitEnv` values in [uds-identity-config](https://github.com/defenseunicorns/uds-identity-config/blob/main/docs/CUSTOMIZE.md#customizing-realm).
+UDS Core ships with a [templated](https://github.com/defenseunicorns/uds-identity-config/blob/main/src/realm.json#L1712-L1813) Google SAML IDP, more documentation to configure the `realmInitEnv` values in [uds-identity-config](https://uds.defenseunicorns.com/reference/uds-core/idam/customization/#customizing-realm).
 
 Alternatively, the `realmInitEnv` can be configured via bundle overrides like in the [k3d-standard-bundle](https://github.com/defenseunicorns/uds-core/blob/main/bundles/k3d-standard/uds-bundle.yaml#L96).