Splitting an argument should not cause max arity to be exceeded

[remkop]

If an option has arity="2", then it should consume two command line arguments following the option name, regardless of whether those command line arguments are split or not.

Currently if a value is split into three parts, only two are considered to be option parameters, the third part is discarded.

Instead, the two command line arguments following the option name should be consumed (since the option's arity is 2), regardless of how many parts they may be split up in.