Add patching grammar to docstring

src/cpp/include/UTIL/CheckCollections.h

@@ -57,6 +57,23 @@ namespace UTIL {
  Vector getConsistentCollections() const ;
 
  /** Add a collection with (name,type) that should be added to events in patchEvent().
+ *
+ * Depending on the contents of name and type one of the following things
+ * will happen:
+ *
+ * - if type is an LCIO type an empty collection of the given type will be
+ put into the event using the passed name
+ * - if type is `LCRelation[<from-type>,<to-type>]` an LCRelation collection
+ * will be created setting the <from-type> and <to-type> as FromType and
+ * ToType collection parameters.
+ * - if type contains a '|' the whole (name, type) pair will be considered
+ * to be ParticleID meta information and the name will be used as a PID
+ * algorithm name and the type information will be parsed as
+ * <reco-coll-name>|[<param-name>,<param-names...>], I.e. a ParticleID
+ * algorithm of name will be attached to the ReconstructedParticle
+ * collection with name <reco-coll-name>. Additionally any parameter names
+ * that are in the comma-separated list after the '|' will be set via the
+ * PIDHandler for this ParticleID algorithm
  */
  void addPatchCollection(std::string name, std::string type);