Update with new save methods.

Author: kpinnipa

docs/user/ux.rst

@@ -7,6 +7,8 @@ Add snippet
 ^^^^^^^^^^^
 * Drag code cell(s) to panel.
 * Highlight code and save as snippet.
+* Select cell(s) and use context menu to save as snippet.
+* Select cell(s) and use keyboard shortcut to save (cmd-shift-A or ctrl-shift-A).
 * Click plus button on panel to create a custom snippet.
 
 Find snippet