presentation improvements for mcb and scb

[kohlhase]

currently, {mcb} and {scb} could use a bit more love in the presentation. In the moment,

  \begin{subproblem}
    There is a walk from $a$ to $b$ that visits each \sr{node}{vertex} of $G$ ...
    \begin{subproblem}
      ...at most once.
      \begin{scb}[style=inline]
        \scc[T]{\sn{constant}}
        \scc{\sn{linear}, i.e. $\atmost{\natplus{\card\nodes,\card\edges}}$}
        \scc{\sn{polynomial}}
        \scc{\sn{exponential}}
      \end{scb}
    \end{subproblem}

(from MathHub/problems/maai-test/source/logic/prob/graph-complexities-lutz.en.tex gives

with

below.

There are a couple of problems:

• [x] there is no space after the circle (even though there is a ~ in the \scc macro; weird.
• [ ] The footnotes for the result are wasteful, we should just juse \circledcirc from amssymb.sty for the [T] case of \scc and only have the footnotes if there is feedback via Ttext for Ftext. For the [T] case of \mcc we could use something like \makebox[0pt][l]{$\square$}\raisebox{.15ex}{\hspace{0.1em}$\checkmark$}

[Jazzpirate]

done