Field and value completion does not work inside conditionals

[VeryMilkyJoe]

Cabal completion seems to not be able to complete anything inside if statements.

Here, the default completion for vscode is suggested inside an if conditional, when it should be the library section fields:

Here, the exposed modules values should be completed instead of the default vscode completions:

The fields we are checking for completion are defined here.
I think to fix this we can check the parent sections recursively instead of simply the most direct parent to figure out the stanza the cursor is located in.

[fendor]

Do we need to change the Context then?

[VeryMilkyJoe]

Do we need to change the Context then?

I don't think it is necessary to change the type of Context for this issue, since we do not care whether we are inside a conditional for the completion.
We can simple set the StanzaContext to the nearest parent which is a Stanza.

[fendor]

@dyniec is taking a stab at this 🎊