docs: Fix typo in pw_docgen

Change-Id: Ibeb86e93fa190dd7187f8cc556330810c87d1886
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/54040
Commit-Queue: Adam MacBeth <amacbeth@google.com>
Reviewed-by: Wyatt Hepler <hepler@google.com>
diff --git a/pw_docgen/docs.rst b/pw_docgen/docs.rst
index bcb1d61..595be1c 100644
--- a/pw_docgen/docs.rst
+++ b/pw_docgen/docs.rst
@@ -54,7 +54,7 @@
   <https://pypi.org/project/sphinxcontrib-mermaid/>`_ package.
 
 Documentation source and asset files are placed alongside code within a module
-and registered as a ``pw_docgen_group`` target within a ``BUILD.gn`` file. These
+and registered as a ``pw_doc_group`` target within a ``BUILD.gn`` file. These
 groups become available for import within a special documentation generation
 target, which accumulates all of them and renders the resulting HTML. This
 system can either be used directly within Pigweed, or integrated into a