Broken flags after function definition with named args

[amiller27]

fish version: fish, version 3.0.2-1620-g055a3321
OS: Ubuntu 18.04
Terminal: terminator

a7913c3 (the fix for #6147) breaks function definitions that look like this:

function _pisces_bind_pair -a mode left right -d "Creates bindings for the given pair: autoclose and skip closing symbol"

Definitions like this are common in packages, that example is taken from laughedelic/pisces, it also breaks oh-my-fish/theme-bobthefish and probably others. It seems like the solution would be to assume the argument names end when another flag is encountered instead of erroring out.

[faho]

breaks function definitions

Not quite. The function definition was already broken, in that the options were never applied (instead variables with those names were defined), only fish never complained.

However I agree that this isn't an acceptable way to fail.

We should just pass all free arguments (those not belonging to any option) to --argument-names if it has been given (excluding the first of course, because that's the function name).

For the time being, let's revert a7913c3.

[amiller27]

Even arguments that are passed before --argument-names or after other options? So in the definition

function foo a --argument-names b --no-scope-shadowing c

the argument names would be a b c? That seems much less intuitive than what I was intending to do in my PR (treat non-options between --argument-names and the next option as the argument names) but if that's what you want I can change the PR.