`showLoading` and `showUndo` "ignore" `isHTML = true`

The showLoading and showUndo functions somewhat "ignore" isHTML = true, because they don't simply pass the text argument to showMessage, which itself just forwards it to Toastify, but they create a new element and set its innerText property to the value of text and then pass the whole element to showMessage.

https://github.com/nextcloud-libraries/nextcloud-dialogs/blob/c32717e1a0593f043a52a6b5bf9c42d427503d50/lib/toast.ts#L213-L223

I think it would be fine to do

const loaderContent = document.createElement('div')
loaderContent[options.isHTML ? 'innerHTML' : 'innerText'] = text

The containers are flex containers, so I think it won't be a problem

https://github.com/nextcloud-libraries/nextcloud-dialogs/blob/c32717e1a0593f043a52a6b5bf9c42d427503d50/styles/toast.scss#L23-L28

If you don't want to change this, I think it would be a good idea to at least remove isHTML from the options

export function showLoading(text: string, options?: Omit<ToastOptions, 'isHTML'>): Toast { }

Start in lib/toast.ts around lines 213-223 to inspect how showLoading and showUndo handle text and isHTML. Check styles/toast.scss around lines 23-28, then verify that HTML text is rendered as intended without breaking the toast layout.