feat(chezmoi): add completion plugin (#12696)

plugins/chezmoi/README.md

@@ -0,0 +1,11 @@
+# chezmoi Plugin
+
+## Introduction
+
+This `chezmoi` plugin sets up completion for [chezmoi](https://chezmoi.io).
+
+To use it, add `chezmoi` to the plugins array of your zshrc file:
+
+```bash
+plugins=(... chezmoi)
+```