DashDash token causing remaining parameter tokens to be flagged as CommandName

Apparently there is some special meaning to the DashDash token when it is used in command mode, but I couldn’t seem to uncover it. While trying to understand the tokenizer and parser I ran in to these two issues:

1. A DashDash token causes further Parameter tokens to be flagged as CommandName, which can be confusing with PSReadLine if PSReadLine if changed to prioritize the highlighting of CommandName over Parameter (https://github.com/PowerShell/PSReadLine/pull/989).
2. A DashDash token can be accepted as a command, when used with the invoke operators, but it does not get flagged with CommandName, and so causes PSReadLine to highlight it as a operator. Even when it is accepted as a command, the behavior in point 1 still occurs.

Steps to reproduce

& -- -NowACommandNameFlaggedToken

[BrucePay]

@vexx32 Since @msftrncs seemed unclear, I just wanted to point out that there is, in fact, a very specific meaning to -- (and --%).

[msftrncs]

I also see this happening for the --% verbatim argument syntax.

& --% this is now one large argument verbatim

where --% is actually a command name, but the rest of the command line is one single verbatim argument.