[NTG-context] Check for parity of pair tags on source file to be closed

[Wolfgang Schuster]

Pablo Rodriguez schrieb am 10.01.2020 um 21:32:
> On 1/10/20 1:46 PM, context at vivaldi.net wrote:
>> Hello Pablo,
>>
>> thanks for your suggestion.
>>
>> The "check" detected "\startitemize" which stayed open on the end of the
>> file, but did not detect "\if++" without correspondng "\fi".
> Hi Lukas,
>
> I don’t know whether checking for \if...\fi pairs is even implemented.

It shoudn't even be needed in a normal document because we have modes 
and \bgroup/\egroup can be replaced with \start/\stop.

Wolfgang