Allow breaking cross-reference of tokens in a `productionlist` by StanFromIreland · Pull Request #148845 · python/cpython

I'll find the relevant rules to link instead, when I'm at a desk.
(The rule names are different between the docs & the grammar; I'm slowly syncing them but in the mean time it's a bit confusing.)

If you do want to to suppress the linking, you can omit the backquotes entirely -- the literal node this PR adds doesn't have semantic meaning. Don't do that here though.