Remove magic-doc-links from code.
Remove magic-doc-links from code.

This change contains no code changes. Only doc-strings.

We can't use relative links in code files, so we don't have much choice but to link to tensorflow.org/

The deleted links were to docs that no longer exist.

PiperOrigin-RevId: 209019572

tensorflow/docs,tensorflow/docs,tensorflow/docs-l10n,tensorflow/docs