Fix grammatical error in custom_layer docs

[NikSchaefer]

Fix a grammatical error within the custom layer docs:

Change "... common layers as a well as easy ways for you to ..." to "common layers as well as easy ways for you to"

[github-actions]

Preview

Preview and run these notebook edits with Google Colab:

• site/en/tutorials/customization/custom_layers.ipynb

Rendered notebook diffs available on ReviewNB.com.

Format and style

Use the TensorFlow docs notebook tools to format for consistent source diffs and lint for style:

$ python3 -m pip install -U --user git+https://github.com/tensorflow/docs

$ python3 -m tensorflow_docs.tools.nbfmt notebook.ipynb

$ python3 -m tensorflow_docs.tools.nblint --arg=repo:tensorflow/docs notebook.ipynb

If commits are added to the pull request, synchronize your local branch: git pull origin patch-1

[8bitmp3]

Thank you!