wrong font shape for `@var` in `@example`

[Werner LEMBERG]

[texinfo.tex 2022-08-20.19]

I'm *very* unhappy that `@var` in `@example` environments no longer
produce slanted typewriter but slanted roman – with ligatures!
Besides being extremely ugly, it completely ruins the fixed-width
spacing, which is of paramount importance.  Please, PLEASE revert
this.

The attached images show the output of

```
\input texinfo.tex

@example
flubb flabb flubb flabb flubb flabb
flubb flabb @var{flubb} @var{flabb} flubb flabb
flubb flabb flubb flabb flubb flabb
@end example

@bye
```

The 'old' image was produced with `texinfo.tex` version 2022-04-10.11.

I can only repeat my strong concerns that I've already voiced on the
'texinfo' mailing list: Patrice's ideas of redesigning some commands
and its affected font changes should be done by adding new commands,
leaving the old ones unchanged for backward compatibility.  Otherwise
chances are very high that you get such unwanted collateral damage as
demonstrated here.


    Werner