New OutputEvent category for highly visible output messages

[polinasok]

According to the spec, there are now four categories:
category?: 'console' | 'stdout' | 'stderr' | 'telemetry' | string;

I don't know how other editors treat these, but in vscode console, stdout and stderr all go to the same place (Debug Console). And they are usually used for target's output as well as continuous logging from the debugger or client. That stream of messages can be a lot to process and critical things can go unnoticed. It would be quite useful if there was an additional category that received special emphasis and could be used for extra critical one-off messages that really need to stand out and not get overlooked by the user. Additional context is here: microsoft/vscode#111718.

[weinand]

I suggest to add a new value important to the Output event's category property.
(if you have suggestions for a better name, please let me know)

Its description text will explain that this is a "hint" for the client to make the message highly visible, e.g. by using a presentation style that makes it stand out from other output debug console messages or by showing a popup notification.
If a client does not understand important, the value console is assumed.

Please note that this mechanism cannot be used to ask the user for input.

Here is the new important value embedded in the category property of the Output event:

/** The output category. If not specified or if the category is not understand by the client, 'console' is assumed.
    Values:
       'console': Show the output in the client's default message UI, e.g. a 'debug console'.
            This category should only be used for informational output from the debugger (as opposed to the debuggee).
       'important': A hint for the client to show the ouput in the client's UI for important and highly visible information,
            e.g. as a popup notification. This category should only be used for important messages from the debugger 
            (as opposed to the debuggee). Since this category value is a hint, clients might ignore the hint and assume
            the 'console' category.
       'stdout': Show the output as normal program output from the debuggee.
       'stderr': Show the output as error program output from the debuggee.
       'telemetry': Send the output to telemetry instead of showing it to the user.
       etc.
*/
category?: 'console' | 'important' | 'stdout' | 'stderr' | 'telemetry' | string;

@polinasok what do you think?

[weinand]

Since there was no opposition, I'll release the proposal.

[polinasok]

Thank you for addressing this. Sounds good.