Code lenses for Run/Debug links on main methods don't show up immediately

Environment

• Operating System: macOS 10.13
• JDK version: 1.8
• Visual Studio Code version: 1.27.2
• Java extension version: 0.31.0
• Java Debugger extension version: 0.13.0

Steps To Reproduce

1. Create a simple java class
2. Copy and paste this main method into the class

	public static void main(String[] args) {
		System.out.print("hello");
	}

3. Run/Debug code lenses don't show up
4. Save file or type any character in the file
5. Run/Debug code lenses show up

Current Result

Run/Debug code lenses don't show up immediately

Expected Result

Run/Debug code lenses should show up immediately after the public static main method is added