bug#39326: [EWW] submit buttons are displayed differently in Emacs 24 and Emacs 27

[Denis Ah-Kang]

Hi,

I was recently helping someone debug a web page displayed in
EWW and I found out that Emacs 24 and Emacs 27 (and maybe earlier 
versions) don't render the submit buttons the same way.

Let's take the following markup:
<button type="submit">Accept</button>

With Emacs 24, EWW will display that button with the text "Accept" but
with Emacs 27, the text is "Submit".

Note, if there's a name attribute, Emacs 27 will display that attribute
instead.

Trying with other text browsers such as lynx or w3m, they all display
the text node. Do you know if EWW intentionally display 'Submit' for
all these buttons? This can be a accessibility problem when there are
multiple forms and submit buttons on the same page as the buttons
will all be displayed the same way.

Thanks,

Denis