bug#8795: 24.0.50; `completion-try-completion' addition of METADATA arg

[Stefan Monnier]

> 1. The addition of arg METADATA, without making it optional, breaks
> existing code that calls the function with only the first four args.
 
Indeed, it was meant as an internal function, tho clearly it was never
fully internal since icomplete uses it.

I'll see how I can fix it, but in the mean time, could you tell me how
you use it (I can guess the"where" is "icicles")?


        Stefan