Support official Github copilot LSP and allow to install the latest LSP version

[kiennq]

Support official Github copilot LSP and allow to install the latest LSP version via copilot-version = nil.

[Kaylebor]

I've been trying to have copilot reference a local install of the LSP, like this on my config.el (Doom Emacs):

(after! copilot
  (setq copilot-server-executable (expand-file-name "~/.bun/bin/copilot-language-server")))

I have also tried:

(use-package! copilot
  :after copilot
  :config (setq copilot-server-executable (expand-file-name "~/.bun/bin/copilot-language-server")))

The variable is correctly set when checking its value, but copilot.el complains that there's no server installed.
Is the only supported method to use the package-installed LSP, and never a globally-available one? With or without this variable, it fails to find it.

[kiennq]

I've been trying to have copilot reference a local install of the LSP, like this on my config.el (Doom Emacs):

(after! copilot
  (setq copilot-server-executable (expand-file-name "~/.bun/bin/copilot-language-server")))

I have also tried:

(use-package! copilot
  :after copilot
  :config (setq copilot-server-executable (expand-file-name "~/.bun/bin/copilot-language-server")))

The variable is correctly set when checking its value, but copilot.el complains that there's no server installed. Is the only supported method to use the package-installed LSP, and never a globally-available one? With or without this variable, it fails to find it.

Should be fixed in #364