Add inputmode to a note on type="number"

Improve the guidance by mentioning `inputmode` (alongside `pattern`) as
it now has good cross browser support for showing the numeric keypad on
mobile.

A follow up issue will be raised to improve the wording to make a clearer
recommendation to use `inputmode`.

Include names of contributors under Acknowledgements.

Co-authored-by: Hanna Laakso <hanna.laakso@digital.cabinet-office.gov.uk>
Co-authored-by: Mark Green <mark.green@digital.cabinet-office.gov.uk>

source

@@ -46242,8 +46242,9 @@ ldh-str = &lt; as defined in <a href="https://tools.ietf.org/html/rfc1034#
  arrows). Getting a credit card number wrong by 1 in the last digit isn't a minor mistake, it's as
  wrong as getting every digit incorrect. So it would not make sense for the user to select a credit
  card number using "up" and "down" buttons. When a spinbox interface is not appropriate, <code
- data-x="">type=text</code> is probably the right choice (possibly with a <code
- data-x="attr-input-pattern">pattern</code> attribute).</p>
+ data-x="">type=text</code> is probably the right choice (possibly with an
+ <code data-x="attr-inputmode">inputmode</code> or <code data-x="attr-input-pattern">pattern</code>
+ attribute).</p>
 
 
 
@@ -121186,6 +121187,7 @@ INSERT INTERFACES HERE
  Habib Virji,
  Hajime Morrita,
  Hallvord Reiar Michaelsen Steen,
+ Hanna Laakso,
  Hans S. T&oslash;mmerhalt,
  Hans Stimer,
  Harald Alvestrand,
@@ -121433,6 +121435,7 @@ INSERT INTERFACES HERE
  Mark Amery,
  Mark Birbeck,
  Mark Davis,
+ Mark Green,
  Mark Miller,
  Mark Nottingham,
  Mark Pilgrim,