Alias restArgs as restParam

[megawac]

Closes #2209

Related issue (where name was discussed) #2140

In the name of lodash/underdash compatibility I think we should probably drop restArgs in favour of restParam which is closer to what is described in the JavaScript spec (rest parameter). The counter argument is we call them args elsewhere in the library.

Otherwise an alias should be sufficient.

[jdalton]

The counter argument is we call them args elsewhere in the library.

Yep, except a rest parameter isn't plural it's a single param so args (plural) is incorrect no matter how you slice it. Also a function can accept several args but may only have 1 or 2 params. For example _.without from v1.7.0 has 1 param, array, but accepts multiple arguments to filter out.