[doc_checker] Add fuchsia/fontdata to validProjects

Change-Id: I3a87ac3bdac4f5f845efe7c3e720fbc480d28427
diff --git a/tools/doc_checker/lib/projects.dart b/tools/doc_checker/lib/projects.dart
index a68f475..dc961cf 100644
--- a/tools/doc_checker/lib/projects.dart
+++ b/tools/doc_checker/lib/projects.dart
@@ -9,6 +9,7 @@
   'cobalt',
   'experiences',
   'fargo',
+  'fontdata',
   'fuchsia',
   'infra', // This is a family of projects.
   'integration',