Update ui_dropdown.html - Added info about resetSearch

Added information about msg.resetSearch (delete user search term)

Author: DanielsNoJack

nodes/locales/en-US/ui_dropdown.html

@@ -5,6 +5,7 @@
     <p>The configured value of the selected item will be returned as <code>msg.payload</code>.</p>
     <p>Setting <code>msg.payload</code> to one of the item values will preset the choice in the dropdown.
     If using the multi-select option then the payload should be an array of values.</p>
+    <p>Optionally user search term can deleted if set the <code>msg.resetSearch</code> property is present and true.</p>
     <p>Optionally the <b>Topic</b> field can be used to set the <code>msg.topic</code> property.</p>
     <p>The Options may be configured by inputting <code>msg.options</code> containing an array.
     If just text then the value will be the same as the label, otherwise you can specify both by