ENH: expand multicol_align and multirow_align Styler.to_latex #43471
Description
Currently styler only allows multicol_align in {"r", "l", "c", "naive-l", "naive-r"}
Simple pipe characters around multicol_alignment allow dividers to be drawn, e.g. |r or |r| or r| etc..
\begin{tabular}{lllrrrrrr} \toprule {} & {} & {} & \multicolumn{3}{|r|}{1} & \multicolumn{3}{|r|}{2} \\ {} & {} & {} & \multicolumn{2}{r|}{a} & {b} & \multicolumn{2}{|l}{a} & {b} \\ {} & {} & {} & {0} & {0} & {0} & {0} & {0} & {0} \\ \midrule \multirow[t]{3}{*}{1} & \multirow[t]{2}{*}{a} & 0 & -1 & -1 & -1 & -1 & -1 & -1 \\ & & 0 & -1 & -1 & -1 & -1 & -1 & -1 \\ & b & 0 & -1 & -1 & -1 & -1 & -1 & -1 \\ \cline{1-3} \multirow[t]{3}{*}{2} & \multirow[t]{2}{*}{a} & 0 & -1 & -1 & -1 & -1 & -1 & -1 \\ & & 0 & -1 & -1 & -1 & -1 & -1 & -1 \\ & b & 0 & -1 & -1 & -1 & -1 & -1 & -1 \\ \bottomrule \end{tabular} 
Also note the cline (this one might be harder to implement)