Book Marx: Properly format bookmarks.

Change-Id: Idd6f2c4622d4b1a16c74b2d3af02e637625732fc
diff --git a/gradle.properties b/gradle.properties
index 04a46b5..5759eca 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -24,5 +24,6 @@
 jnaVersion = 5.5.0
 jose4jVersion = 0.7.0
 testcontainersVersion = 1.12.4
+flexmarkVersion = 0.60.2
 
 org.gradle.parallel = true