pw_arduino_build: Add missing comma

Also add a missing py.typed file in pw_package.

Change-Id: Iec601a2074afd20b61c704e05ac172fbaf9e525b
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/36180
Pigweed-Auto-Submit: Wyatt Hepler <hepler@google.com>
Reviewed-by: Rob Mohr <mohrr@google.com>
Reviewed-by: Keir Mierle <keir@google.com>
Commit-Queue: Wyatt Hepler <hepler@google.com>
diff --git a/pw_arduino_build/py/setup.py b/pw_arduino_build/py/setup.py
index 0865eb7..528ca95 100644
--- a/pw_arduino_build/py/setup.py
+++ b/pw_arduino_build/py/setup.py
@@ -25,7 +25,7 @@
     package_data={
         'pw_arduino_build': [
             'core_patches/teensy/01-teensyduino_1.53-cpp17.diff',
-            'core_patches/teensy/02-teensy4_nonstatic_flash_functions.diff'
+            'core_patches/teensy/02-teensy4_nonstatic_flash_functions.diff',
             'py.typed',
         ]
     },
diff --git a/pw_package/py/pw_package/packages/py.typed b/pw_package/py/pw_package/packages/py.typed
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/pw_package/py/pw_package/packages/py.typed