chore(mise): remove default gems and go package files

For go packages that's managed directly by mise now, and ruby gems is
the old trust `install_ruby_global_packages` shell function.

default-gems

@@ -1,3 +0,0 @@
-# Default Gems installed by mise when installing new Ruby versions.
-foreman
-rubocop

default-go-packages

@@ -1,4 +0,0 @@
-# Default Go packages installed by mise when installing new Go versions.
-# github.com/nametake/golangci-lint-langserver@latest
-# golang.org/x/tools/cmd/goimports@latest
-# golang.org/x/tools/gopls@latest

install.sh

@@ -21,8 +21,6 @@ SYMLINKS=(
   config/starship.toml
   config/tlrc/config.toml
   config/xkeysnail/config.py
-  default-gems
-  default-go-packages
   erlang
   gemrc
   gitconfig