Problem:
- The document from `go doc` can be very long, and you can scroll if
using `!` to run shell command in Gvim.
- I realize that I didn't fully mimic behavior of default keywordprg
in Nvim in the last commit.
Solution:
- Use builtin terminal for keywordprg in Gvim
- In Nvim (both TUI and GUI), it should mimic the behavior of Vim
`:term`, `:Man`, and `:help`
closes: vim/vim#1691111ab02c819
Co-authored-by: Phạm Bình An <phambinhanctb2004@gmail.com>
Co-authored-by: zeertzjq <zeertzjq@outlook.com>