[feature] make 'Octo comment add' work for visual

[alex-popov-tech]

Issue Description

Type: feature request

Describe what feature you want

Please make 'Octo comment add' work on visual, it will be more consise and understandable than now using OctoAddReviewComment. Also relevant for suggestions.

Anything else we need to know?

Related to #301

[pwntester]

Turns out there was a bug introduced when I changed the mappings to use "vim.keymap.set". I took the opportunity to improve the support for multiline comments and thread buffer responsivness. Please check out latest version and let me know if it works for you now (no need to use OctoAddReview commands, in fact I removed them)

[alex-popov-tech]

its working now like a charm, thank you <3