Improve the set of qmlsc/qmllint messages that get shown in the Issues pane

Current limitations

While qmlsc/qmllint errors and warnings are shown in Qt Creator's Issue Pane, messages that are marked as "Info" (i.e. those that are considered less serious than "Warnings") are not shown there.

Example
Given this code:

import QtQuick
import QtQuick.Controls.Basic

Window {
    width: 640
    height: 480
    visible: true

    Item {
        property string foo
        Item {
            property string bar: foo
        }
    }
}

The qmllint output is:

Info: D:/Dev/Test/Main.qml:2:1: Unused import [unused-imports]
import QtQuick.Controls.Basic
^^^^^^
Warning: D:/Dev/Test/Main.qml:12:25: Unqualified access [unqualified]
            property string bar: foo
                                 ^^^
Info: foo is a member of a parent element.
      You can qualify the access with its id to avoid this warning:

            property string bar: <id>.foo
                                 ^^^^^

However, only "Unqualified access" appears in the Issues pane. "Unused import" does not, even though users probably consider this an issue that they want qmllint to inform them about.

Suggestions and thoughts

We want to get "Unused import" onto the Issues pane somehow. I'm not sure how.

• Make qmllint upgrade "Unused import" to a Warning?
• Give Qt Creator a more advanced algorithm for detecting qmllint issues, compared to https://codereview.qt-project.org/c/qt-creator/qt-creator/+/483236 ?

I'm also not sure if the suggestions for fixing the issue (e.g. "You can qualify the access with its id...") should appear in the Issues pane or not. Please debate away in the comments section.