Remove unused function _zsh_nvm_get

zsh-nvm.plugin.zsh

@@ -12,14 +12,6 @@ _zsh_nvm_has() {
   type "$1" > /dev/null 2>&1
 }
 
-_zsh_nvm_get() {
-  if _zsh_nvm_has "curl"; then
-    curl --silent "$1"
-  elif _zsh_nvm_has "wget"; then
-    wget --quiet --output-document - "$1"
-  fi
-}
-
 _zsh_nvm_latest_release_tag() {
   echo $(cd "$NVM_DIR" && git fetch --quiet origin && git describe --abbrev=0 --tags --match "v[0-9]*" origin)
 }