Support <C-.> keymap

[rogeryk]

Describe the solution you'd like In Golang, when you usually need to reference a exported function or a nested structure. You have to complete a part first, then type ".", repeat again. e.g.

sli // complete
slices // input .
slices. // complete
slices.Clone()

If it is a multi nested structure, it will be more painful, e.g. A.B.C.D

In Vim, I will map <C-.> to these two steps. When I want to do the same in vscodevim, I found that vscodevim. It does not seem to support <c-.>.

[rogeryk]

Looks like it's just need to add some configuration, which should be pretty simple