wrong ts.d for XacroLoader

[ajs124]

According to the ts.d .load takes the parameters url: string, onLoad: (xml: XMLDocument) => void, options?: XacroLoaderOptions, but the actual implementation (probably) takes a string and two functions, so the ts.d should probably say something like load(url: string, onLoad: (xml: XMLDocument) => void, onError: (err: Error) => void): Promise<XMLDocument> instead.

[Garrett Johnson]

Hello! Thanks for the catch -- looks like the js files got out of sync with the types. Do you want to create a PR to update the d.ts file? The README is up to date with the latest function signatures.