Combine Gitaly and Gitaly Cluster intro information

doc/administration/geo/index.md

@@ -54,7 +54,7 @@ Geo provides:
 ### Gitaly Cluster
 
 Geo should not be confused with [Gitaly Cluster](../gitaly/praefect.md). For more information about
-the difference between Geo and Gitaly Cluster, see [Gitaly Cluster compared to Geo](../gitaly/praefect.md#gitaly-cluster-compared-to-geo).
+the difference between Geo and Gitaly Cluster, see [Gitaly Cluster compared to Geo](../gitaly/index.md#gitaly-cluster-compared-to-geo).
 
 ## How it works
 

doc/administration/gitaly/configure_gitaly.md

@@ -5,7 +5,7 @@ info: To determine the technical writer assigned to the Stage/Group associated w
 type: reference
 ---
 
-# Configure Gitaly
+# Configure Gitaly **(FREE SELF)**
 
 The Gitaly service itself is configured by using a [TOML configuration file](reference.md).
 

doc/administration/gitaly/reference.md

@@ -5,7 +5,7 @@ info: To determine the technical writer assigned to the Stage/Group associated w
 type: reference
 ---
 
-# Gitaly reference
+# Gitaly reference **(FREE SELF)**
 
 Gitaly is configured via a [TOML](https://github.com/toml-lang/toml)
 configuration file. Unlike installations from source, in Omnibus GitLab, you