Remove stray period.

PiperOrigin-RevId: 597644351
Change-Id: Ib37f1d52307c4b1a4ab7c3cff5b83f2d664d6dc8
diff --git a/api-guidelines/ndk.md b/api-guidelines/ndk.md
index c71615a..010e353 100644
--- a/api-guidelines/ndk.md
+++ b/api-guidelines/ndk.md
@@ -299,7 +299,7 @@
 
 6.  For NDK APIs, **documentation must be in Doxygen syntax.** To appear on DAC,
     all documentation (including `@file`) must be contained by a `@defgroup` or
-    `@addtogroup`. block.
+    `@addtogroup` block.
 
     Doxygen is not required for APEX, but API documentation in some form is.
     Prefer Doxygen when adding new documentation. Note to API reviewers: