Add XML documentation for Org.Apache.Http.Client.Methods

[jonathanpeppers]

The Org.Apache.Http.Client.Methods namespace contains 56 To be added placeholders in source XML documentation (excluding docs\xml\index.xml).

rg -n -i --glob 'Org.Apache.Http.Client.Methods/**' --glob 'ns-Org.Apache.Http.Client.Methods.xml' 'to be added' docs\xml