Add XML documentation for Org.XmlPull.V1

[jonathanpeppers]

The Org.XmlPull.V1 namespace contains 174 To be added placeholders in source XML documentation (excluding docs\xml\index.xml).

rg -n -i --glob 'Org.XmlPull.V1/**' --glob 'ns-Org.XmlPull.V1.xml' 'to be added' docs\xml

Update log

• 2026-09-10: Refreshed the placeholder scan from 183 to 174 (reduced by 9). Related documentation PRs: #463, #635, #644.