Shellcheck as a new shell linter + runtime.go out of git control

[alikefia]

No description provided.

[alikefia]

Found a custom way (from init.lua)

linter.removeLinter("shfmt")
linter.makeLinter("shellcheck", "shell", "shellcheck", {"-f", "gcc", "%f"}, "%f:%l:%c:.+: %m")

[alikefia]

@zyedidia, 2 questions please

1. do you want to change / add shellcheck linter in default config ?
2. agree to remove runtime.go from git control ?

[zyedidia]

Shellcheck is fine. Let's keep runtime.go for now because it makes it possible to install using go get/go install. I think we can remove it when we switch to using the built-in embed package at some point in the future.

[alikefia]

Done ! runtime.go regenerated...