Clarify a code comment

Author: silvanocerza

Diff for: commands/instances.go

@@ -842,7 +842,7 @@ func Upgrade(ctx context.Context, req *rpc.UpgradeRequest, downloadCB DownloadPr
 
 // LoadSketch collects and returns all files composing a sketch
 func LoadSketch(ctx context.Context, req *rpc.LoadSketchRequest) (*rpc.LoadSketchResponse, error) {
-	// TODO: This a ToRpc function for the Sketch struct
+	// TODO: This should be a ToRpc function for the Sketch struct
 	sketch, err := sk.New(paths.New(req.SketchPath))
 	if err != nil {
 		return nil, fmt.Errorf("error loading sketch %v: %v", req.SketchPath, err)