Use builtin echo to avoid conflicts with user aliases

When users have an alias or function that shadows 'echo', it can break
autosuggestions by either printing wrong suggestions or executing
unwanted functions. This commit replaces all 'echo' calls with
'builtin echo' to ensure the shell's built-in echo is always used.

Fixes: #843

src/async.zsh

@@ -34,12 +34,12 @@ _zsh_autosuggest_async_request() {
 	# Fork a process to fetch a suggestion and open a pipe to read from it
 	builtin exec {_ZSH_AUTOSUGGEST_ASYNC_FD}< <(
 		# Tell parent process our pid
-		echo $sysparams[pid]
+		builtin echo $sysparams[pid]
 
 		# Fetch and print the suggestion
 		local suggestion
 		_zsh_autosuggest_fetch_suggestion "$1"
-		echo -nE "$suggestion"
+		builtin echo -nE "$suggestion"
 	)
 
 	# There's a weird bug here where ^C stops working unless we force a fork

src/strategies/completion.zsh

@@ -39,7 +39,7 @@ _zsh_autosuggest_capture_completion_widget() {
 	fi
 
 	# The completion has been added, print the buffer as the suggestion
-	echo -nE - $'\0'$BUFFER$'\0'
+	builtin echo -nE - $'\0'$BUFFER$'\0'
 }
 
 zle -N autosuggest-capture-completion _zsh_autosuggest_capture_completion_widget

src/util.zsh

@@ -7,5 +7,5 @@ _zsh_autosuggest_escape_command() {
 	setopt localoptions EXTENDED_GLOB
 
 	# Escape special chars in the string (requires EXTENDED_GLOB)
-	echo -E "${1//(#m)[\"\'\\()\[\]|*?~]/\\$MATCH}"
+	builtin echo -E "${1//(#m)[\"\'\\()\[\]|*?~]/\\$MATCH}"
 }

zsh-autosuggestions.zsh

@@ -128,7 +128,7 @@ _zsh_autosuggest_escape_command() {
 	setopt localoptions EXTENDED_GLOB
 
 	# Escape special chars in the string (requires EXTENDED_GLOB)
-	echo -E "${1//(#m)[\"\'\\()\[\]|*?~]/\\$MATCH}"
+	builtin echo -E "${1//(#m)[\"\'\\()\[\]|*?~]/\\$MATCH}"
 }
 
 #--------------------------------------------------------------------#
@@ -534,7 +534,7 @@ _zsh_autosuggest_capture_completion_widget() {
 	fi
 
 	# The completion has been added, print the buffer as the suggestion
-	echo -nE - $'\0'$BUFFER$'\0'
+	builtin echo -nE - $'\0'$BUFFER$'\0'
 }
 
 zle -N autosuggest-capture-completion _zsh_autosuggest_capture_completion_widget
@@ -791,12 +791,12 @@ _zsh_autosuggest_async_request() {
 	# Fork a process to fetch a suggestion and open a pipe to read from it
 	builtin exec {_ZSH_AUTOSUGGEST_ASYNC_FD}< <(
 		# Tell parent process our pid
-		echo $sysparams[pid]
+		builtin echo $sysparams[pid]
 
 		# Fetch and print the suggestion
 		local suggestion
 		_zsh_autosuggest_fetch_suggestion "$1"
-		echo -nE "$suggestion"
+		builtin echo -nE "$suggestion"
 	)
 
 	# There's a weird bug here where ^C stops working unless we force a fork