Offer no suggestion for single constructor

[JaroslavTulach]

Pull Request Description

Resolving #5055 - avoid putting single constructor into suggestion database.

Important Notes

Another way to fix #5055 is to keep the single constructor information in the suggestion database and let the IDE filter that out.

Checklist

Please include the following checklist in your PR:

• The documentation has been updated if necessary.
• All code conforms to the
  Scala,
  style guides.
• All code has been tested:
  • Unit tests have been written where possible.

[JaroslavTulach]

@jdunkerley seems to be OK with this change. What do @4e6 and @hubertp think?

[hubertp]

So what about Pair.Value? that takes two parameters, should that not be reported in suggestion DB either?

[JaroslavTulach]

So what about Pair.Value? that takes two parameters, should that not be reported in suggestion DB either?

Pair.Value is a great example and there may be others.

Pair.Value is marked as UNSTABLE - users are likely supposed to use Pair.new. E.g. not including the constructor in suggestion DB in this case is probably OK... if that's what @Frizi and @jdunkerley want.

[hubertp]

I would probably limit this to a hardcoded Value to avoid some unexpected behaviour. Up to you if you want to include that.

[jdunkerley]

So what about Pair.Value? that takes two parameters, should that not be reported in suggestion DB either?

Pair.Value is a great example and there may be others.

Pair.Value is marked as UNSTABLE - users are likely supposed to use Pair.new. E.g. not including the constructor in suggestion DB in this case is probably OK... if that's what @Frizi and @jdunkerley want.

Pair.Value should indeed be hidden from users. Pair.new is supposed to be the method that users create it.

In general, the goal was that we wouldn't show a drop down for things with a single constructor as that (probably) isn't what we want.