C#: Explicitly add QL Doc for the LdapInjectionConfig predicates.

Author: michaelnebel

csharp/ql/lib/semmle/code/csharp/security/dataflow/LDAPInjectionQuery.qll

@@ -43,10 +43,20 @@ deprecated class TaintTrackingConfiguration extends TaintTracking::Configuration
  * A taint-tracking configuration for unvalidated user input that is used to construct LDAP queries.
  */
 module LdapInjectionConfig implements DataFlow::ConfigSig {
+  /**
+   * Holds if `source` is a relevant data flow source.
+   */
   predicate isSource(DataFlow::Node source) { source instanceof Source }
 
+  /**
+   * Holds if `sink` is a relevant data flow sink.
+   */
   predicate isSink(DataFlow::Node sink) { sink instanceof Sink }
 
+  /**
+   * Holds if data flow through `node` is prohibited. This completely removes
+   * `node` from the data flow graph.
+   */
   predicate isBarrier(DataFlow::Node node) { node instanceof Sanitizer }
 }