Merge pull request #1359 from OwenTuz/issue-1190-document-capitalisation-of-dn

LDAP connector - Document that 'DN' must be in capitals

Documentation/connectors/ldap.md

@@ -43,6 +43,8 @@ Dex currently allows insecure connections because the project is still verifying
 
 User entries are expected to have an email attribute (configurable through `emailAttr`), and a display name attribute (configurable through `nameAttr`). `*Attr` attributes could be set to "DN" in situations where it is needed but not available elsewhere, and if "DN" attribute does not exist in the record.
 
+For the purposes of configuring this connector, "DN" is case-sensitive and should always be capitalised.
+
 The following is an example config file that can be used by the LDAP connector to authenticate a user.
 
 ```yaml