added 'Bind to grammar/schema file' command to Commands.md

Author: Alexander Chen

docs/Commands.md

@@ -4,9 +4,15 @@
 
 ![XML Commands](images/Commands/XMLCommands.png)
 
+## Bind to grammar/schema file
+
+This command triggers the [XML Binding Wizard]() for the current file.
+
+If the current XML document is not bound using an `xml-model` tag or a root element doesn't have a `xsi:noNameSpaceLocation` attribute, the command will have the user select a `.xsd/.dtd` grammar file to bind to the XML document. Otherwise, an error will be thrown on the client if the XML document already has a bound grammar/schema.
+
 ## Open XML Documentation
 
-This command opens the `XML Documentation`
+This command opens the `XML Documentation`.
 
 ## Revalidate current XML file