js-utils bootstrapForm with input groups doesn't display error correctly

[georgehemmings]

I've found an issue when using bootstrapForm to show input errors next to input groups when using Bootstrap 4.

To demo the issue, I've forked the Validation project and changed the textbox on Full Name to be a input group with a textbox and a button. See this commit georgehemmings/Validation@d93068b

If you browse to https://localhost:44310/client-jquery/contacts/ and click the Add Contact button you'll see that the input group is broken up visually as the error message is appended after the text box when it should be placed after the input group.

[mythz]

There was never any support for input groups which aren't properly supported by Bootstrap so this is more a feature request than an issue but I've added support for it in ss-utils.js in this commit which will insert the validation message at the end of the input group although Bootstrap's still doesn't support displaying an invalid-feedback in an input group properly.

This change is available from the latest v5.5.1 that's now available on MyGet.

[georgehemmings]

Cheers. Looks good to me now.