ligatures reinstated (wrongly) by @r, @i, @b, @sansserif, @slanted in texi2any

[Patrice Dumas]

Hello,

In all the formats output by texi2any, except in LaTeX which is
more consistent with TeX, @r, @i, @b, @sansserif and @slanted switch
back to normal context if in code/monospace context.  This is not
the case in LaTeX output, only @r, @cite and @var restore ligatures
for --, ---...

At the same time, font changes are combined (this is the case for LaTeX
too).  This leads to a very inconsistent output, for example
@code{@slanted{a--b}} leads to a typewriter font with -- being rendered
as an en dash and not as two -.

I propose to have only @r, among font commands restore ligatures.  Would
that be ok?

-- 
Pat