Intellsense features do not work with !include

[ReidWeb]

Summary of defect

When using this plugin, my team and I really appreciate the Intellisense features that the plugin gives us to predict participant names for example when authoring a sequence diagram.

However based on our testing, we cannot get such prediction to work when the participants are declared in an external file and included.

I believe my workspace is setup correctly, the preview returns with the 'declared name' fine.

Behaviours

Expected

Feature: IntelliSense/Intelligent prediction

    Scenario: Predict a participant name for a sequence diagram where participant is declared in an included file
        Given I have a participant declared `participant "Service" as SRV`
        And that participant is declared in an external file
        And I have the PlantUML plugin installed
        And I have the `includepaths` setting declared
        When I type `S` into VS Code
        Then Intellisense should return `SRV` as an option in the prediction

Actual

Feature: IntelliSense/Intelligent prediction

    Scenario: Predict a participant name for a sequence diagram where participant is declared in an included file
        Given I have a participant declared `participant "Service" as SRV`
        And that participant is declared in an external file
        And I have the PlantUML plugin installed
        And I have the `includepaths` setting declared
        When I type `S` into VS Code
        Then Intellisense does not return the prediction for SRV

Reproducability

Files as follows

VS Code Settings

{
    "plantuml.includepaths": [
        "common"
    ],
}

common/common_segments.puml

@startuml(id=participants)
participant "Service" as SRV
@enduml(id=participants)

diagrams/my_sequence_diagram.puml

@startuml
!include common_segments!participants

S
@enduml

Use case

You might ask, why are we doing this?

We have a series of sequence diagrams describing a complicated feature, we want to break those down into smaller segments with fewer participants and fewer activities; we don't want to have to re-declare the same participant list across all our diagrams. This has the additional benefit of us being able to rename a participant display name, order or grouping once and have it update across all our diagrams in seconds.