LaTeX 2020-02-02 release

[Arash Esbati]

Hi all,

this message is a heads-up reg. the changes in LaTeX planned for
2020-02-02.  Acc. to ltnews31.tex[1], the following changes have also an
impact for AUCTeX[2, 3]:

    \subsection{Extending the shape management of NFSS}

    Over time more and more fonts have become available for use with
    \LaTeX{}. Many such font families offer additional shapes, e.g.,
    small caps italics (\texttt{scit}), small caps slanted
    (\texttt{scsl} or swash letters (\texttt{sw}). By using
    \cs{fontshape} those shapes can be explicitly selected and for the
    swash letter shapes there is also \cs{swshape} and \cs{textsw}
    available.

    Using \cs{upshape} will still change italics or slanted back to an
    upright shape but will not any longer alter the small caps
    setting. To change small capitals back to upper/lower case you can
    now use \cs{ulcshape} (or \cs{textulc}) which in turn will not
    change the font with respect to italics, slanted or swash. Finally,
    if you want to reset the shape back to normal you can use
    \cs{normalshape} which is a shorthand for \cs{upshape}\cs{ulcshape}.

This change means we have to add 2 entries to `LaTeX-font-list' for
\textsw and \textulc.  I suggest the keys `C-w' and `C-l', i.e.:

    (?\C-l "\\textulc{"     "}")
    (?\C-w "\\textsw{"      "}")

Addition of the declarations \swshape and \ulcshape to latex.el and
font-latex.el will also be necessary.

Next relevant change is this one[4]:

    \subsection{Providing all text companion symbols by default}

    The text companion encoding \texttt{TS1} was originally not
    available by default, but only when the \pkg{textcomp} package was
    loaded. The main reason for this was limited availability in fonts
    other than Computer Modern and memory restrictions back in the
    nineties. These days neither limitation exists anymore so with the
    2020 release all the symbols provided with the \pkg{textcomp}
    package are available out of the box.

This means we have to move all symbols in `textcomp.el' into `latex.el'
and cater for \legacyoldstylenums.

I think the other changes aren't relevant within AUCTeX.  Any comments?

Best, Arash

Footnotes:
[1]  https://github.com/latex3/latex2e/blob/develop/base/doc/ltnews31.tex

[2]  
https://github.com/latex3/latex2e/blob/fb6c6a9433366768f8ed128540538d68837bd5c8/base/doc/ltnews31.tex#L192-L199

[3]  
https://github.com/latex3/latex2e/blob/fb6c6a9433366768f8ed128540538d68837bd5c8/base/doc/ltnews31.tex#L208-L214

[4]  
https://github.com/latex3/latex2e/blob/fb6c6a9433366768f8ed128540538d68837bd5c8/base/doc/ltnews31.tex#L384-L392