Missing <output> in attr_overrides

[KrishnaRPatel]

Line:

glimmer-vm/packages/@glimmer/runtime/lib/dom/props.ts

Line 48 in 25fb030

const ATTR_OVERRIDES: Dict<Dict> = {

Bug:
emberjs/ember.js#19272

Setting an <output>'s form with a non-ancestor form's id should be allowed, but is set as readonly in typescript (as it is in the whatwg idl). <output>'s form attribute is similar to the others (whatwg/html#6165) so we should add the output tag as an additional override here.

[rwjblue]

Fixed by #1209