Docs: fix broken javadoc link

No change to content. This fixes some broken javadoc links. This also
swaps `<code>` tags out in favor of javadoc-style `{@code}` annotation.

Fixes: 399502531
Flag: DOCS_ONLY
Test: make -j20 offline-sdk-docs
Test: cd out/target/common/docs/offline-sdk/ && python3 -m http.server
Change-Id: I27da183a91b012339e7fe75a0ed58638f661cd15