Enable lookahead for argument text object

[jphalip]

This allows motions like caa or dia to look ahead for potential arguments, say when the caret is positioned before the list of arguments. This would work similar to https://github.com/vim-scripts/argtextobj.vim and to standard motions like ci".

[lippfi]

The lookahead doesn't always work

<caret>12 + 100 + myFun(arg1, arg2)

[lippfi]

Could you please have a look at the comments?

[jphalip]

@lippfi Good catch with that failing example. I've made some fixes, which should address that.

[lippfi]

This is what happens when I place caret inside "Hi there :(" and type via

P.S. you could use some useful methods from SearchGroup.kt to skip string ranges