Account for possible Element instance changed when lazily computing d…

[lahodaj]

Consider code like:

public class Test {
|
}

And try to slowly type Tes inside VS Code. This will open code completion, and offer to create an initialize-all constructor. But, when the completion item is confirmed, it sometimes happens the action does not do anything (except removing the typed part of the identifier).

The reason is, I think, that the completion is computed for T, and when typing es, the completion is filtered, but not recomputed. But, reparsing the source code (due to the typed characters) may change Element instances, and the lazy computation for TextEdit for inserting the constructor will try to compare original and current Element for equality, and that will fail.

I am not quite clear why there is the Element check, but it would be better to compare e.g. ElementHandles, not Elements.