This fixes a bug found with #18531: Currently the named argument for generateblock is documented as address/descriptor, but the server only accepts a named argument of address. Fix it by changing the name to output for both the documentation and the server code. Also, add tests to prove the server understands the new name output. Unrelated to that, there have been a bunch of aliases in the server code that are not present in the source code of the documentation. Fix that by adding the alias to the source code of the documentation. Only the first alias is displayed in the rendered documentation. Also, add tests to prove the server actually understands all aliases.
Backport of core PR18607.
Depends on D8567.