Add comment to lintPaths

Test: none
Change-Id: Ia7db6e27fedd95df2ebfc573e35a44a93acb031b
diff --git a/java/lint.go b/java/lint.go
index f9a89d0..5940eac 100644
--- a/java/lint.go
+++ b/java/lint.go
@@ -174,6 +174,8 @@
 		extraLintCheckTag, extraCheckModules...)
 }
 
+// lintPaths contains the paths to lint's inputs and outputs to make it easier to pass them
+// around.
 type lintPaths struct {
 	projectXML android.WritablePath
 	configXML  android.WritablePath