Support file multiple selection

[yezige]

By modifying the older brother's code, it has been tested and I hope you can add this part of the code.

But how do I contribute code?

[yezige]

vscode-copy-relative-path/extension.js:

function activate(context) {
	var disposable = vscode.commands.registerCommand('copyRelativePath', function (uri_first, uris) {
		var copied = '';//the previous copy
		if (!uris.length) {//when editor/title/context did not receive the uris
			uris = [uri_first];
		}
		for (i in uris) {
			var uri = uris[i];
			if (typeof uri === 'undefined') {
				if (vscode.window.activeTextEditor) {
					uri = vscode.window.activeTextEditor.document.uri;
				}
			}
			if (!uri) {
				vscode.window.showErrorMessage('Cannot copy relative path, as there appears no file is opened (or it is very large');
				return;
			}
			var path = vscode.workspace.asRelativePath(uri);
			path = path.replace(/\\/g, '/');
			copied = copy(path, false, copied);
		}
	});
	context.subscriptions.push(disposable);
}

vscode-copy-relative-path/node_modules/copy-paste/index.js:

exports.copy = function (text, callback, copied) {
	text = (copied ? copied + "\n" : '') + text;
	
	//...

	return text;
};