Hi,

I was in the process to convert an itemize part to a description and wanted to simplify the code in the same move.
I discovered headcommand for that, but struggled to set the text in an highlight _and_ make a colon at the end.
Do you know, if this is possible?

Here is a MWE:
```
\definehighlight[hl][style={\m{>}\,\switchtobodyfont[tt]}]

\definedescription[category][
	alternative=top,
	headstyle=bold,
	width=broad,
]

\definedescription[desc][
	width=broad,
	distance={\widthofstring{~}},
	headcommand={\groupedcommand{\hl}{:}},
	% headcommand={\groupedcommand{}{:}}, % this compiles but the highlight is lost
	% headcommand={\groupedcommand{\starthl}{\stophl :}}, % this does not compile
	headstyle=,
	before={\startpacked},
	after={\stoppacked},
	alternative=hanging,
]

\starttext

This is a \hl{highlight}.

Some listings

\startcategory{Itemize}
	\startitemize[packed]
		\item \hl{first}: one
		\item \hl{second}: two
	\stopitemize
\stopcategory

Now the same as desc:
\startcategory{Desc}
	\startdesc{first} one \stopdesc
	\startdesc{second} two \stopdesc
\stopcategory

\stoptext
```
The itemize looks like it should look (except of the dots).

Best,
Gerion