Fixed "no lintable files found" error when navigating to Swift interface files

[FelixLisczyk]

I'm using the xcode-build-server project to work with Xcode projects in VS Code. Whenever I to navigate to a symbol (Cmd + Click) inside a Swift framework (e.g. JSONDecoder or UUID), SwiftLint throws the following error:

2
cd /Users/felix/Developer/Swift/Apps/TelemetryViewer &&  SCRIPT_INPUT_FILE_0='../../../../../../var/folders/ms/lrk4_z852q595bcwwfh0ftcm0000gn/T/GeneratedInterfaces/Foundation.swiftinterface' SCRIPT_INPUT_FILE_COUNT='1' '/opt/homebrew/bin/swiftlint'  'lint' '--use-script-input-files' '--quiet' '--reporter' 'json'
extensionHostProcess.js:147
Error: Unexpected SIGPIPE
	at process.<anonymous> (/Applications/Visual Studio Code.app/Contents/Resources/app/out/bootstrap.js:1:471)
	at process.emit (/Users/felix/Developer/Misc/VS Code Plugins/vscode-swiftlint/lib/events.js:513:28)
	at Signal.callbackTrampoline (node:internal/async_hooks:130:17) {stack: 'Error: Unexpected SIGPIPE
	at process.<anonym…Trampoline (node:internal/async_hooks:130:17)', message: 'Unexpected SIGPIPE'}

extensionHostProcess.js:147
2
stderr Error: No lintable files found at paths: ''

In this example, the lintable file path (request.document.uri.fsPath) contains the following value: /var/folders/ms/lrk4_z852q595bcwwfh0ftcm0000gn/T/GeneratedInterfaces/Foundation.swiftinterface

Since I don't see any reason to run SwiftLint on read-only system framework files, I've added a check to skip .swiftinterface files.

Note: This is my first time working on VS Code plugins. Please feel free to make edits to my code. 😊