chore(docs): add documentation for hiding service URLs

Author: SteKoe

spring-boot-admin-docs/src/site/docs/customize/01-customize_ui.md

@@ -76,7 +76,7 @@ spring:
             enabled: false
 ```
 
-## Hide Service URL ==
+## Hide Service URL
 
 To hide service URLs in Spring Boot Admin UI entirely, set the following property in your Server's configuration: