Methods to add markup to inputfield after Description and/or before Notes

[Toutouwai]

Short description of the enhancement

The Inputfield class has a prependMarkup() method: this inserts markup at the start of .InputfieldContent, meaning it appears before the inputfield Description.

It also has an appendMarkup() method: this inserts markup at the end of .InputfieldContent, meaning it appears after the inputfield Notes.

This request is for a couple of new methods (or maybe new options for those two existing methods?) so that markup can be inserted after the Description and/or before the Notes.

Why would the enhancement be useful to users?

Sometimes there's a need to add input-related markup to an inputfield, and you want it to appear between the Description and the Notes so the editor understands that the Description and Notes are relevant to the added markup too.