Feature request: add an "Attribute editor" or "key-value editor" header

Steps to reproduce:

• open Inkscape
• open the XML editor
• click on the "show attributes" toggle button in the XML editor

What happened?

In the XML editor you can see a "show attributes" toggle button. That opens a screen with Key, Value labels and an "add new attribute" button inside. Unfortunately that screen doesn't have a header.

What should have happened?

A header should be added to the screen such as "attribute editor" or "key-value editor" (the latter would be a more accurate name because that screen isn't only used for editing XML attributes, but also for text node values). It is useful for it to have a header so that it is referable in conversation.

Inkscape Version and Operating System:

• Inkscape Version: 1.0beta1
• Operating System: Windows
• Operating System version: 7, 32-bit