fixed spelling mistake at selectWinodw Commnad

Author: Jongkeun

packages/selenium-ide/src/neo/models/Command.js

@@ -509,7 +509,7 @@ class CommandList {
     [ "selectWindow", {
       name: "select window",
       description: "Selects a popup window using a window locator. Once a popup \
-                    window has been selected, all commands wll go to that window. \
+                    window has been selected, all commands will go to that window. \
                     To select the main window again, use null as the target. \
                     Window locators provide different ways of specifying the window \
                     object: by title or by generated id.",