object element doesn't do anything in forms [was: Issue #1314]

[siusin]

Re-file Issue #1314 from programmer3000.

from programmer3000:

<object> element not explain case how form attribute associated with <form> element and haven't example for this. Maybe form attribute for <object> element should be removed from HTML specification. What form attribute really do with <object> element, for what it now?
And nothing tell about value of form attribute: ID of <form> element
https://www.w3.org/TR/html/semantics-embedded-content.html#elementdef-object

[chaals]

Submitting an object doesn't seem to work or be documented anywhere, and the closest thing in wwg spec is "try to get a value from a plugin" (otherwise the object doesn't take part in the form).

Since we deprecated plugins we should deprecate this mechanism as unimplemented.