Fix dot-repeat for Vim change operators

[zasdaym]

Closes #73.

[badranx]

Hey thanks for the PR. I tested the ciw and it works, diw didn't. Another point is that this repo should keep changes to Helix source code minimal and simple. Rebasing on Helix should be a simple task that anyone could do it quickly.

We also need to keep :vim-disable/:vim-enable working (which can be achieved by creating a custom vim command instead of changing Helix's).

For example, we put most logic for vim commands in helix-term/src/commands/vim_patch.rs‎ to reduce changes to Helix master branch.

I should add these contributions info somewhere, sorry.