update KDL scope to text to match upstream changes

[eugenesvk]

Description

The KDL package changed main scope from source to text since it's a doc, not a programming language. This does the same in AFileIcon

Motivation and Context

Upstream package change, partially avoids issues such as #56

How Has This Been Tested?

Locally opening KDL files and seeing their scope. This change doesn't fully resolve the issue (will open a separate issue), but it's still a necessary step

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

I think this might introduce theme overriding issues for old versions of KDL package?

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have read the CONTRIBUTING document.

[eugenesvk]

Is something similar needs to be done with to retain the old scope? preferences/file_type_kdl.tmPreferences

[deathaxe]

Yeah, tmPreferences are automatically generated by calling (unpublished) make.cmd prefs on Windows.

icons.json is actually only the meta data source to create aliases, create and tint icons and create tmPreferences files.