Fix vi-mode partial-accept

Issue #188. PR #324.

Thanks to @toadjaune and @IngoHeimbach.

src/widgets.zsh

@@ -153,7 +153,7 @@ _zsh_autosuggest_execute() {
 
 # Partially accept the suggestion
 _zsh_autosuggest_partial_accept() {
-	local -i retval
+	local -i retval cursor_loc
 
 	# Save the contents of the buffer so we can restore later if needed
 	local original_buffer="$BUFFER"
@@ -165,13 +165,19 @@ _zsh_autosuggest_partial_accept() {
 	_zsh_autosuggest_invoke_original_widget $@
 	retval=$?
 
+	# Normalize cursor location across vi/emacs modes
+	cursor_loc=$CURSOR
+	if [[ "$KEYMAP" = "vicmd" ]]; then
+		cursor_loc=$((cursor_loc + 1))
+	fi
+
 	# If we've moved past the end of the original buffer
-	if (( $CURSOR > $#original_buffer )); then
+	if (( $cursor_loc > $#original_buffer )); then
 		# Set POSTDISPLAY to text right of the cursor
-		POSTDISPLAY="$RBUFFER"
+		POSTDISPLAY="${BUFFER[$(($cursor_loc + 1)),$#BUFFER]}"
 
 		# Clip the buffer at the cursor
-		BUFFER="$LBUFFER"
+		BUFFER="${BUFFER[1,$cursor_loc]}"
 	else
 		# Restore the original buffer
 		BUFFER="$original_buffer"