feat: add zsh-autosuggestions and zsh-syntax-highlighting (#14088)

Closes #12865
Closes #11995
Closes #12864

plugins/zsh-autosuggestions/README.md

@@ -0,0 +1,16 @@
+# zsh-autosuggestions
+
+This plugin suggests commands as you type, based on command history and completions.
+
+To use it, add `zsh-autosuggestions` to the plugins array in your zshrc file:
+
+```zsh
+plugins=(... zsh-autosuggestions)
+```
+
+Start a new terminal session after updating your zshrc file.
+
+Suggestions appear in muted gray text by default. Press <kbd>→</kbd> or <kbd>End</kbd> at the end of the
+command line to accept the displayed suggestion.
+
+For configuration options and additional key bindings, see the [upstream documentation](MANUAL.md).