Add support for actions on `/` (index) route

Describe the feature

I think it would be great if the library supports form actions on the / route via server/actions/index.ts. Currently this is not possible, because the parser recognizes index.ts as a form action for the route /index:

form-actions-nuxt/packages/form-actions-nuxt/src/runtime/utils.ts

Lines 5 to 10 in 4ba9695

    
           export function getActionRoute(actionPath: string) { 
        
             const actionRegex = /.*actions[\/\\](.*?)\.ts/ 
        
             const actionRoute = actionRegex.exec(actionPath)?.[1] 
        
             if (!actionRoute) throw new Error(`Could not parse action route from ${actionPath}`) 
        
             return actionRoute 
        
           }

Additional information

Would you be willing to help implement this feature?

	export function getActionRoute(actionPath: string) {
	const actionRegex = /.actions[\/\\](.?)\.ts/
	const actionRoute = actionRegex.exec(actionPath)?.[1]
	if (!actionRoute) throw new Error(`Could not parse action route from ${actionPath}`)
	return actionRoute
	}