bug#49558: fill paragraph in texinfo-mode fails with @

[Stefan Monnier]

>> --
>> Lines that start a new paragraph and are
>> contained in it must match only ‘paragraph-start’, not
>> ‘paragraph-separate’. 
>> --
>
> I never took this seriously.  E.g., even our default values of these
> variables don't seem to heed this rule.
>
> Stefan, any comments?

I do remember some fuzzily-obeyed rule about relationship between these
two vars, but this one seems to be non-fuzzy: if a line matches
`paragraph-separate` then its content is not considered as being part of
a refillable paragraph, IOW its content will be left alone, never
cutting it shorter or adding to it text from the following line.

In which sense do our default values not heed this rule?


        Stefan