Part Xcamelize 2

SourceEditorCommand.swift

class SourceEditorCommand: NSObject, XCSourceEditorCommand {
    
    func perform(with invocation: XCSourceEditorCommandInvocation, completionHandler: @escaping (Error?) -> Swift.Void ) {
       ...
    }
    
    func handle(range: XCSourceTextRange, inBuffer buffer: XCSourceTextBuffer) -> () {
        ...
    }
    
    func getTextFromBuffer(inRange textRange: XCSourceTextRange, inBuffer buffer: XCSourceTextBuffer) -> String {
        ...
    }
    
    func replace(position: XCSourceTextPosition, length: Int, with newElements: String, inBuffer buffer: XCSourceTextBuffer) {
        ...
    }   
}