docs: Add copyright statement to toml template I missed adding the statement so I added them here to prevent others from forgetting to add the statement. BUG=None TEST=Documentation change only Change-Id: I2d75baede4820a8a294d08ce7d1c1c28b355cfbd Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/bazel/+/5999878 Reviewed-by: Matt Stark <[email protected]> Tested-by: John L Chen <[email protected]> Commit-Queue: John L Chen <[email protected]>