docs: Updated SECURITY_PATCH field description

Test: make ds-docs -j32

Bug: 127625306
Change-Id: I052bb647ebb36ea3c9a788be592e7de9cd969e10
diff --git a/core/java/android/os/Build.java b/core/java/android/os/Build.java
index 77d367f..176c2b7 100755
--- a/core/java/android/os/Build.java
+++ b/core/java/android/os/Build.java
@@ -243,7 +243,8 @@
         public static final String BASE_OS = SystemProperties.get("ro.build.version.base_os", "");
 
         /**
-         * The user-visible security patch level.
+         * The user-visible security patch level. This value represents the date when the device
+         * most recently applied a security patch.
          */
         public static final String SECURITY_PATCH = SystemProperties.get(
                 "ro.build.version.security_patch", "");