Add XML documentation for Java.Util.Zip #256

The Java.Util.Zip namespace contains 111 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 'Java.Util.Zip/**' --glob 'ns-Java.Util.Zip.xml' 'to be added' docs\xml

Update log

• 2026-10-02: Placeholder count refreshed from 275 to 111 (decreased by 164).
• 2026-09-10: Refreshed the placeholder scan from 278 to 275 (reduced by 3). Related documentation PRs: #466, #469, #471, #581, #644.