feat(bun): add plugin (#11859)

plugins/bun/bun.plugin.zsh

@@ -0,0 +1,14 @@
+# If Bun is not found, don't do the rest of the script
+if (( ! $+commands[bun] )); then
+  return
+fi
+
+# If the completion file doesn't exist yet, we need to autoload it and
+# bind it to `bun`. Otherwise, compinit will have already done that.
+if [[ ! -f "$ZSH_CACHE_DIR/completions/_bun" ]]; then
+  typeset -g -A _comps
+  autoload -Uz _bun
+  _comps[bun]=_bun
+fi
+
+bun completions >| "$ZSH_CACHE_DIR/completions/_bun" &|