The partial method doesn't support kwarg-only syntax

[jaredcwhite]

While working on the roda-turbo plugin, it dawned on me that the partial method doesn't support a keyword arguments-only signature. You can do this:

partial "path/to/template", locals: { abc: 123 }

But not this:

partial template: "path/to/template", locals: { abc: 123 }

Which makes it hard to pass rendering options for the turbo_stream tag builder directly to partial. We should support both signatures.