Refresh current buffer when formatter is running in watch mode and fix slow build

[vedant-pandey]

When making any change in a file with this command running in the background two things happen

• The file doesn't refresh immediately and I need to either switch back-n-forth or enter :e for the file to get the formatter changes
• The build appears to be too slow? I'm not sure if it has to do with the lsp or build caching but taking reference from go lsp, that feels more instant and snappy. Hope this is helpful!

dune build --watch @fmt --auto-promote @all

https://github.com/user-attachments/assets/2916dd77-ea7b-4979-ae36-fcafc165949c