Several improvements to UI and supported files.

New features:
- new simple UI.
- support for .strings, .ini and .cfg files.
- support for .xib and .storyboard files as XML.
- preview can show custom source file.
- better support for standard preprocessor for many file format (if you have previously customized the preprocessor for some formats please check if it require to add the placeholder $targetHL).
- highlight updated to 3.57.
Bugfix:
- rust file extension.
- settings migration.

Author: sbarex

Application/AppDelegate.swift

@@ -151,8 +151,8 @@ class AppDelegate: NSObject, NSApplicationDelegate {
                 NSWorkspace.shared.activateFileViewerSelecting([u])
             } else {
                 let alert = NSAlert()
-                alert.messageText = "Attention"
-                alert.informativeText = "The application support folder don't exists."
+                alert.window.title = "Attention"
+                alert.messageText = "The application support folder don't exists."
                 alert.addButton(withTitle: "Close")
                 alert.alertStyle = .informational