Little text to clarify what the '*' means in forms

src/utils/modeHandler.js

@@ -92,13 +92,15 @@ export class Modal extends Component {
         const config = this.configGetter();
         if (config && 'displayMode' in config) {
             if (config.configurable && config.displayMode === "settings") {
-                return (
+                return [
                 <Form
                     className = "container"
                     schema={this.modes.settingsSchema}
                     onSubmit={this.handleSettingsChange.bind(this)}
                     formData={config}
-                    liveValidate={true} />);
+                    liveValidate={true} />,
+                <br/>,
+                <p className="container"><span clasName="required">*</span> : required field</p>];
             }
             if (config.hasReadme && config.displayMode === "readme") {
                 return this.modes.readme;