Allow loading the plugin in the background

If zle is already active (plugin has been loaded in the background),
just start the widgets and set up the automatic re-binding (if manual
rebind has not been specified).

See GitHub issue #481

src/start.zsh

@@ -21,5 +21,11 @@ _zsh_autosuggest_start() {
 # Mark for auto-loading the functions that we use
 autoload -Uz add-zsh-hook is-at-least
 
-# Start the autosuggestion widgets on the next precmd
-add-zsh-hook precmd _zsh_autosuggest_start
+# If zle is already running, go ahead and start the autosuggestion widgets.
+# Otherwise, wait until the next precmd.
+if zle; then
+	_zsh_autosuggest_start
+	(( ! ${+ZSH_AUTOSUGGEST_MANUAL_REBIND} )) && add-zsh-hook precmd _zsh_autosuggest_start
+else
+	add-zsh-hook precmd _zsh_autosuggest_start
+fi

zsh-autosuggestions.zsh

@@ -854,5 +854,11 @@ _zsh_autosuggest_start() {
 # Mark for auto-loading the functions that we use
 autoload -Uz add-zsh-hook is-at-least
 
-# Start the autosuggestion widgets on the next precmd
-add-zsh-hook precmd _zsh_autosuggest_start
+# If zle is already running, go ahead and start the autosuggestion widgets.
+# Otherwise, wait until the next precmd.
+if zle; then
+	_zsh_autosuggest_start
+	(( ! ${+ZSH_AUTOSUGGEST_MANUAL_REBIND} )) && add-zsh-hook precmd _zsh_autosuggest_start
+else
+	add-zsh-hook precmd _zsh_autosuggest_start
+fi