docs: Remove unused extensions

Change-Id: I37d0a067486263493e507465674a237c5ab25beb
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/examples/+/287592
Pigweed-Auto-Submit: Kayce Basques <kayce@google.com>
Lint: Lint 🤖 <android-build-ayeaye@system.gserviceaccount.com>
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Reviewed-by: Rob Mohr <mohrr@google.com>
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diff --git a/docs/conf.py b/docs/conf.py
index 2ad33f4..5795a10 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -41,8 +41,6 @@
 
 extensions = [
     'pw_docgen.sphinx.google_analytics',  # Enables optional Google Analytics
-    'pw_docgen.sphinx.module_metadata',
-    'pw_docgen.sphinx.seed_metadata',
     'sphinx.ext.autodoc',  # Automatic documentation for Python code
     'sphinx.ext.napoleon',  # Parses Google-style docstrings
     'sphinxarg.ext',  # Automatic documentation of Python argparse