docs: update list of commands that <init options> can be used for

[muzimuzhi]

List in package manual, beginning of sec. 5 Initialization Option Keys, which is not updated since it was firstly documented in v3.05:

tcolorbox/doc/latex/tcolorbox/tcolorbox.doc.initoptions.tex

Lines 6 to 16 in 92fd467

	The \emph{initialization} options are only applicable for the generation
	of new environments and commands based on |tcolorbox| and friends.
	Particularly, they can be used for
	\begin{itemize}
	\item\refCom{newtcolorbox},
	\item\refCom{newtcbox},
	\item\refCom{newtcblisting},
	\item\refCom{newtcbinputlisting},
	\item\refCom{newtcbtheorem}, and
	\item\refCom{newtcboxfit}.
	\end{itemize}

Full list as of v6.0.1:

- \newtcolorbox,        \NewTColorBox,      \NewTotalTColorBox
- \newtcbox,            \NewTCBox,          \NewTotalTCBox
- \newtcblisting,       \NewTCBListing
- \newtcbinputlisting,  \NewTCBInputListing
- \newtcbtheorem,       \NewTcbTheorem
- \newtcboxfit,         \NewTCBoxFit,       \NewTotalTCBoxFit

Among them the \NewTC... variants may be considered not very necessary to be listed , but \NewTotalTC... ones, from my point of view, worth to be added.

[T-F-S]

I think it does not hurt to enlarge this list for next version.

[T-F-S]

Done with https://github.com/T-F-S/tcolorbox/releases/tag/v6.0.2