`@code` doesn't allow line break after first `-`

[Werner LEMBERG]

[texinfo.tex 2023-01-08.15]


Consider the following input.

```
\input texinfo

@tracingall
@tracingonline0

@code{foo-bar}

@code{foo-bar-baz}

@bye
```

For the first `@code` I get the following.

```
...@texttt f
...@texttt o
...@texttt o
...@texttt -
...@texttt b
...@texttt a
...@texttt r
```

For the second one I get

```
...@texttt f
...@texttt o
...@texttt o
...@texttt -
...@texttt b
...@texttt a
...@texttt r
...@texttt -
...@discretionary
...@texttt b
...@texttt a
...@texttt z
```

In other words, `texinfo.tex` doesn't insert a `@discretionary` after
the first `-` character.  This is clearly a bug.


    Werner