Add XML documentation for Java.Util.Zip

[jonathanpeppers]

The Java.Util.Zip namespace contains 275 To be added placeholders in source XML documentation (excluding docs\xml\index.xml).

rg -n -i --glob 'Java.Util.Zip/**' --glob 'ns-Java.Util.Zip.xml' 'to be added' docs\xml

Update log

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