Don't use `-s` option to `zmodload`

It is not available in zsh versions older than 5.3

src/strategies/completion.zsh

@@ -87,7 +87,7 @@ _zsh_autosuggest_capture_buffer() {
 }
 
 _zsh_autosuggest_capture_completion() {
-	zmodload -s zsh/zpty || return
+	zmodload zsh/zpty 2>/dev/null || return
 
 	typeset -g completion
 	local line REPLY

zsh-autosuggestions.zsh

@@ -557,7 +557,7 @@ _zsh_autosuggest_capture_buffer() {
 }
 
 _zsh_autosuggest_capture_completion() {
-	zmodload -s zsh/zpty || return
+	zmodload zsh/zpty 2>/dev/null || return
 
 	typeset -g completion
 	local line REPLY