Add XML documentation for Javax.Crypto #269

The Javax.Crypto namespace contains 44 To be added placeholders in source XML documentation (excluding docs\xml\index.xml).

Finishability

Finishability: not assessed. The TODO count does not establish whether official Android/Java reference comments exist for every remaining member. A source-coverage pass is still needed; if the official comments are exhausted, use a separately agreed completion approach (for example, reviewed authored documentation based on an authoritative source) rather than another importer pass.

rg -n -i --glob 'Javax.Crypto/**' --glob 'ns-Javax.Crypto.xml' 'to be added' docs\xml

Update log

• 2026-10-02: Placeholder count rechecked at 44 (unchanged).
• 2026-09-10: Refreshed the placeholder scan from 47 to 44 (reduced by 3). Related documentation PRs: #383, #502, #644.