Changes

<code>\tab</code> is (a <code>description </code> created with <code>{{cmd|definedescription}}[tab]</code>) starts an indented paragraph with a word or two (the 'key') in front of it. <code>\setuptab</code> configures styles and dimensions for <code>\tab</code>. By default, it leaves 4em for the key and 2em of space between the key area and the paragraph, the latter thanks to <code>width=broad</code>. <code>width=fit</code> leaves no space in between. In mkiv, <code>width=fit</code> leaves 1em of space between the key space and the paragraph; this is probably a bug.