Update docs

Author: kazariad

src/site/antora/modules/ROOT/pages/manual/pattern-layout.adoc

@@ -1298,20 +1298,24 @@ threadPriority
 [#converter-uuid]
 ==== UUID
 
-Includes either a random or a time-based UUID
+Includes a random, time-based, or hash-based UUID.
 
 .link:../javadoc/log4j-core/org/apache/logging/log4j/core/pattern/UuidPatternConverter.html[`UuidPatternConverter`] specifier grammar
 [source,text]
 ----
-u{RANDOM|TIME}
-uuid{RANDOM|TIME}
+u{RANDOM|TIME|HASH}
+uuid{RANDOM|TIME|HASH}
 ----
 
-The time-based UUID is a Type 1 UUID generated using the MAC address of each host
+The random UUID is a Type 4 UUID.
+
+The time-based UUID is a Type 1 UUID generated using the MAC address of each host.
 To ensure uniqueness across multiple JVMs and/or class loaders on the same host, a random number between 0 and 16,384 will be associated with each instance of the UUID generator class, and included in each time-based UUID generated.
 See also xref:manual/systemproperties.adoc#log4j.uuid.sequence[`log4j.uuid.sequence`].
 Because time-based UUIDs contain the MAC address and timestamp, they should be used with care.
 
+The hash-based UUID is a custom Type 8 UUID generated by hashing the LogEvent object.  This deterministic UUID is useful for correlating logs when using multiple Appenders.
+
 [#format-modifiers]
 === Format modifiers