Important: #73227 - TSconfig option altIcons restored

See forge#73227


The TSconfig option altIcons, introduced in forge#35891, allowed to add / override icons for TCA select items. This option was then accidentally removed without further notice, while reworking the FormEngine.

Therefore and because it's sometimes necessary to use different icons for already defined select items - depending on the current page or site context - the option is restored.

The usage is as following:

TCEFORM.pages.doktype.altIcons {
   1 = custom-icon-identifier
   2 = EXT:my_ext/path/to/icon.svg

For more information you can also have a look at the initial changelog.