Improve macros in GOV.UK Frontend

[timpaul]

Related stories and issues

• Make it easier to add a hint or an error message to a fieldset Make it easier to add a hint or an error message to a fieldset #1166
• Tables: Consider enabling array iteration in macros Tables: Consider enabling array iteration in macros #570
• Add an icon next to an input using the govuk Input macro Add an icon next to an input using the govukInput macro #924
• Allow details component to be callable Consider making more components callable #941
• Date input does not allow attributes to be passed to the fieldset govukDateInput not allowing "attribute" property to change for fieldset option #1478
• Add label or legend param to date-input Add label or legend param to date-input #1155
• Macro documentation is confusing #930
• Test for empty items in radios and checkboxes #1494
• Radios and checkboxes with empty conditionals causes odd spacing Radios and checkboxes with empty conditionals causes odd spacing #1546
• Provide a way to import all macros Provide a way to import all macros #1278

[NickColley]

I've documented a potential spike that could help us understand improvements to macros:

#1669

[36degrees]

Closing in favour of the nunjucks label.