Fix links to moved customization docs

doc/administration/index.md

@@ -68,11 +68,10 @@ Learn how to install, configure, update, and maintain your GitLab instance.
 
 #### Customizing GitLab's appearance
 
-- [Header logo](../customization/branded_page_and_email_header.md): Change the logo on all pages and email headers.
-- [Favicon](../customization/favicon.md): Change the default favicon to your own logo.
-- [Branded login page](../customization/branded_login_page.md): Customize the login page with your own logo, title, and description.
-- [Welcome message](../customization/welcome_message.md): Add a custom welcome message to the sign-in page.
-- ["New Project" page](../customization/new_project_page.md): Customize the text to be displayed on the page that opens whenever your users create a new project.
+- [Header logo](../user/admin_area/appearance.md#navigation-bar): Change the logo on all pages and email headers.
+- [Favicon](../user/admin_area/appearance.md#favicon): Change the default favicon to your own logo.
+- [Branded login page](../user/admin_area/appearance.md#sign-in--sign-up-pages): Customize the login page with your own logo, title, and description.
+- ["New Project" page](../user/admin_area/appearance.md#new-project-pages): Customize the text to be displayed on the page that opens whenever your users create a new project.
 - [Additional custom email text](../user/admin_area/settings/email.md#custom-additional-text-premium-only): Add additional custom text to emails sent from GitLab. **(PREMIUM ONLY)**
 
 ### Maintaining GitLab
@@ -105,7 +104,7 @@ Learn how to install, configure, update, and maintain your GitLab instance.
 ## User settings and permissions
 
 - [Creating users](../user/profile/account/create_accounts.md): Create users manually or through authentication integrations.
-- [Libravatar](../customization/libravatar.md): Use Libravatar instead of Gravatar for user avatars.
+- [Libravatar](libravatar.md): Use Libravatar instead of Gravatar for user avatars.
 - [Sign-up restrictions](../user/admin_area/settings/sign_up_restrictions.md): block email addresses of specific domains, or whitelist only specific domains.
 - [Access restrictions](../user/admin_area/settings/visibility_and_access_controls.md#enabled-git-access-protocols): Define which Git access protocols can be used to talk to GitLab (SSH, HTTP, HTTPS).
 - [Authentication and Authorization](auth/README.md): Configure external authentication with LDAP, SAML, CAS and additional providers.

doc/install/installation.md

@@ -183,7 +183,7 @@ sudo make prefix=/usr/local install
 # When editing config/gitlab.yml (Step 5), change the git -> bin_path to /usr/local/bin/git
 ```
 
-For the [Custom Favicon](../customization/favicon.md) to work, GraphicsMagick
+For the [Custom Favicon](../user/admin_area/appearance.md#favicon) to work, GraphicsMagick
 needs to be installed.
 
 ```sh

doc/user/admin_area/settings/email.md

@@ -8,7 +8,7 @@ You can customize some of the content in emails sent from your GitLab instance.
 
 ## Custom logo
 
-The logo in the header of some emails can be customized, see the [logo customization section](../../../customization/branded_page_and_email_header.md).
+The logo in the header of some emails can be customized, see the [logo customization section](../appearance.md#navigation-bar).
 
 ## Custom additional text **(PREMIUM ONLY)**