Add option to split diff in current tab instead of new tab.

[jebby]

I added the option signify_newtab which defaults to 1 for the current behavior of splitting the diff in a new tab.

If g:signify_newtab or b:signify_newtab is set to 0, when :SignifyDiff is called, the split is made in the current tab.

[mhinz]

Hi,

I won't add even more options to this plugin, actually I'm in the process of removing some of them.

How about making :SignifyDiff! (note the !) do this? This would roughly follow typical Vim behaviour.

[mhinz]

Thanks for bringing that to our attention! ✨