[analysis_server] Autocompletion suggestion for redirecting factory constructors shouldn't add arguments

[parlough]

When auto-completing a call to another constructor when declaring a redirecting factory constructor, arguments shouldn't be added to the result since they can't be specified.

class A {
  A.a(int value);

  factory A.b(int value) = A[!]
}

Autocompleting at the [!] results in:

class A {
  A.a(int value);

  factory A.b(int value) = A.a(value)
}

I would expect:

class A {
  A.a(int value);

  factory A.b(int value) = A.a
}

[keertip]

/cc @bwilkerson

[scheglov]

https://dart-review.googlesource.com/c/sdk/+/356141