Update to remove extra Header

Update to remove extra Ldap Authentication Section Header

docs/manual/src/docs/asciidoc/index.adoc

@@ -914,8 +914,6 @@ public BCryptPasswordEncoder passwordEncoder() {
 }
 ----
 
-==== LDAP Authentication
-
 === Multiple HttpSecurity
 
 We can configure multiple HttpSecurity instances just as we can have multiple `<http>` blocks. The key is to extend the `WebSecurityConfigurationAdapter` multiple times. For example, the following is an example of having a different configuration for URL's that start with `/api/`.