docs(guide/migration): document a BC to ngAria (d06431e)

[gkalpak]

No description provided.

[gkalpak]

The BC description is a little vague (and there is no guidelines on how to modify ones code), because I am not sure myself (yet) 😃

[Narretz]

The way I understand it is that this should not affect any apps, because it corrects that aria behavior? It's just technically a BC because the aria-multiline support has been removed.

[gkalpak]

I was confused, because this MDN article says you should put aria-multiline on <textarea>, but after further reading, I believe it's incorrect (possibly outdated).
There's a second part: Previously, the aria-multiline attribute was added to elements with a type or role of textbox (possibly custom multiline text input fields). I am not sure, if removing support for those was an oversight and if it was intentional then does it mean that the user should add it manually (or maybe that it's not possible to have a custom multilne text input (for reasons I am not aware of)).

[gkalpak]

After talking with @marcysutton, it is indeed not needed to add aria-multiline on <textarea elements.
Also, as she correctly pointed out, there is no way to tell if a custom input with [role="textbox"] is multiline or not, so we shouldn't add aria-multiline there either.

I've update the PR. PTAL
/cc @marcysutton

[Narretz]

of textbox?

[gkalpak]

Right :)

[Narretz]

One typo, another suggestion, otherwise LGTM

[gkalpak]

Thx, @Narretz !
(Backported to v1.5.x as 0cc636b.)