Correct the directory count in blink public API documentation

Bug: None
Change-Id: I5308a19ad12f3b0ba59c33bef603f2ff5a0882a8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2523439
Commit-Queue: Kevin McNee <mcnee@chromium.org>
Commit-Queue: Jeremy Roman <jbroman@chromium.org>
Auto-Submit: Kevin McNee <mcnee@chromium.org>
Reviewed-by: Jeremy Roman <jbroman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#825021}
diff --git a/third_party/blink/public/README.md b/third_party/blink/public/README.md
index eb60433..682ee65 100644
--- a/third_party/blink/public/README.md
+++ b/third_party/blink/public/README.md
@@ -21,7 +21,7 @@
 Organization
 ------------
 
-The API is organized into two parts:
+The API is organized into three parts:
 
   - public/common
   - public/platform