Fix typo in the LDAP docs missing a required colon

What does this MR do?

Fixes a typo in the LDAP docs

Why was this MR needed?

As mentioned in the docs already, the following line did not work with a customer:

(memberOf:1.2.840.113556.1.4.1941=CN=My Group,DC=Example,DC=com)

As per the MSDN docs referenced, it should be in the following format:

(memberOf:1.2.840.113556.1.4.1941:=CN=My Group,DC=Example,DC=com)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?