fix wording in options

options.html

@@ -19,7 +19,7 @@
 <input id="length" type="number" min="6" max="100" value="25" name=length class=panel-formElements-item/><label for=length class=panel-formElements-item>Search length (characters) (default 25, sane values are from 25 to 50)</label><br>
 <input id="scale" type="number" min="0.1" max="64" value="1" name=scale class=panel-formElements-item step="0.1"/><label for=scale class=panel-formElements-item>Lookup popup scale</label><br>
 <input id="width" type="number" min="100" max="10000" value="600" name=width class=panel-formElements-item/><label for=width class=panel-formElements-item>Lookup popup width (before scaling)</label><br>
-<input id="lookuprate" type="number" min="1" max="1000" value="8" name=lookuprate class=panel-formElements-item/><label for=lookuprate class=panel-formElements-item>Lookup rate</label><br>
+<input id="lookuprate" type="number" min="1" max="1000" value="8" name=lookuprate class=panel-formElements-item/><label for=lookuprate class=panel-formElements-item>Lookup throttle (milliseconds)</label><br>
 <p>This extension uses JMdict, which is Copyright © 2017 The Electronic Dictionary Research and Development Group and licensed under the <a href="https://creativecommons.org/licenses/by-sa/3.0/">CC BY-SA 3.0</a> license.</p>
 <p>This extension is otherwise licensed under the <a href="https://www.apache.org/licenses/LICENSE-2.0">Apache License, version 2.0</a>.</p>
 <div><p>Meanings of abbreviations follow. From JMdict. Some may be unused. Unsorted.<p>