Only initialize the suggest pickers on input and select elements

The suggest pickers are initialized on every element that has their CSS class, whatever the element is. For example, suggestPages.js calls suggestPages() on .suggest-pages, and the same goes for .suggest-spaces, .suggest-users, .suggest-groups, .suggest-attachments, .suggest-propertyValues, .suggest-childPages and .suggest-wikis.

These class names are generic, so a page or an extension can use one of them on an element that is not a form field, for instance to style it. The picker then tries to turn that element into a selectize widget.

The pickers should only be initialized on the form fields they can enhance, i.e. input and select elements having the class.

This was raised in https://github.com/xwiki/xwiki-platform/pull/5999#discussion_r4442205172 about the new wiki picker, which follows the selector of the existing pickers.